How do the "Weaker" GM's make a living?

I'm not a US citizen but I agree entirely with your sentiments, don't these new stadium proposals have to pass some sort of local vote though to go through? In which case it seems like you and I appear to hold a minority view.

Just to name a few people on chess.com, IM David Pruess,  IM Daniel Rensch, GM Sam Shankland, and WGM Natalia Pogonina all make their money from chess (in some way) I believe. Most of them are in the 2400s, while Sam I think has recently shot up higher than that. IM John Bartolomew also said he decided on chess as his profession, and he's "only" about 2500. I would suppose there are a lot of minor things chess professionals are involved with that add up: coaching, writing, lecturing, playing, promoting, might not seem like much when it comes to chess, but when you combine all of these little things together it might become sufficient.

Here in Arboga, Sweden lives GM Ulf Andersson, once top-10 in the world, and he just playes chess. At least some years ago he got a artist salary from the goverment. I think also he is playing in clubs down in Europe. I assume these clubs or he has sponors. For all I know, he don't have a "ordinary" job.

 Mr Andersson would have made a decent chunk of money in the 1970's and 80's when he was more like top 5 player. He played in all the Super GM Tournaments and apart from actual prize money I'm sure there was appearance money involved as well. Of course most of his money would have come from his royalties as the saxophone player with Abba...

GMs have absolutely no difficulty making a living. Getting there though requires tons of money .. coaching, tournament fees, travel expenses etc.

by beating up even "weaker" guys

they could also do some lawnmowing for cash

lol yeah, everyone can.

i also loled but for different reason 

In my case, I work at an office...well, I´m not a GM, but I work at an office anyway.

I like when that happens, you can argue with people who have probably already dead.

Possibly of interest:
"... the NM title is an honor that only one percent of USCF members attain. ..." - IM John Donaldson (2015)
http://www.jeremysilman.com/shop/pc/Reaching-the-Top-77p3905.htm
What It Takes to Become a Chess Master by Andrew Soltis
"... going from good at tactics to great at tactics ... doesn't translate into much greater strength. ... You need a relatively good memory to reach average strength. But a much better memory isn't going to make you a master. ... there's a powerful law of diminishing returns in chess calculation, ... Your rating may have been steadily rising when suddenly it stops. ... One explanation for the wall is that most players got to where they are by learning how to not lose. ... Mastering chess ... requires a new set of skills and traits. ... Many of these attributes are kinds of know-how, such as understanding when to change the pawn structure or what a positionally won game looks like and how to deal with it. Some are habits, like always looking for targets. Others are refined senses, like recognizing a critical middlegame moment or feeling when time is on your side and when it isn't. ..." - GM Andrew Soltis (2012)
https://web.archive.org/web/20140708093409/http://www.chesscafe.com/text/review857.pdf
100 Chess Master Trade Secrets by Andrew Soltis
https://web.archive.org/web/20140708094523/http://www.chesscafe.com/text/review916.pdf
Reaching the Top?! by Peter Kurzdorfer
"... On the one hand, your play needs to be purposeful much of the time; the ability to navigate through many different types of positions needs to be yours; your ability to calculate variations and find candidate moves needs to be present in at least an embryonic stage. On the other hand, it will be heart-warming and perhaps inspiring to realize that you do not need to give up blunders or misconceptions or a poor memory or sloppy calculating habits; that you do not need to know all the latest opening variations, or even know what they are called. You do not have to memorize hundreds of endgame positions or instantly recognize the proper procedure in a variety of pawn structures.
[To play at a master level consistently] is not an easy task, to be sure ..., but it is a possible one. ..." - NM Peter Kurzdorfer (2015)
http://www.thechessmind.net/blog/2015/11/16/book-notice-kurzdorfers-reaching-the-top.html
http://www.jeremysilman.com/shop/pc/Reaching-the-Top-77p3905.htm
"Yes, you can easily become a master. All you need to do is some serious, focused work on your play.
That 'chess is 99% tactics and blah-blah' thing is crap. Chess is several things (opening, endgame, middlegame strategy, positional play, tactics, psychology, time management...) which should be treated properly as a whole. getting just one element of lay and working exclusively on it is of very doubtful value, and at worst it may well turn out being a waste of time." - IM pfren (August 21, 2017)
"Every now and then someone advances the idea that one may gain success in chess by using shortcuts. 'Chess is 99% tactics' - proclaims one expert, suggesting that strategic understanding is overrated; 'Improvement in chess is all about opening knowledge' - declares another. A third self-appointed authority asserts that a thorough knowledge of endings is the key to becoming a master; while his expert-friend is puzzled by the mere thought that a player can achieve anything at all without championing pawn structures.
To me, such statements seem futile. You can't hope to gain mastery of any subject by specializing in only parts of it. ..." - FM Amatzia Avni (2008)
https://www.chess.com/article/view/can-anyone-be-an-im-or-gm
http://www.cbsnews.com/news/kids-fight-stereotypes-using-chess-in-rural-mississippi/
http://brooklyncastle.com/
https://www.chess.com/article/view/don-t-worry-about-your-rating
https://www.chess.com/article/view/am-i-too-old-for-chess
https://www.chess.com/article/view/how-can-older-players-improve
Train Like a Grandmaster by Kotov
Becoming a Grandmaster by Keene
What It Takes to Become a Grandmaster by GM Andrew Soltis
"BENJAMIN FINEGOLD (born Sep-06-1969 ...) ... Ben became a USCF Life Master at 15, USCF Senior Master at 16, an International Master in 1989, and achieved his final GM norm at the SPICE Cup B Section in September, 2009. ..."
http://www.chessgames.com/player/benjamin_finegold.html
"MARK IZRAILOVICH DVORETSKY (... died Sep-26-2016 ...) ... He was ... awarded the IM title in 1975. Dvoretsky was also a FIDE Senior Trainer and noted author. ... During the 1970s, Mark was widely regarded by the strongest IM in the world, ..."
http://www.chessgames.com/player/mark_izrailovich_dvoretsky.html
"To become a grandmaster is very difficult and can take quite a long time! ... you need to ... solve many exercises, analyse your games, study classic games, modern games, have an opening repertoire and so on. Basically, it is hard work ... It takes a lot more than just reading books to become a grandmaster I am afraid." - GM Artur Yusupov (2013)
http://www.qualitychess.co.uk/ebooks/QandAwithArturYusupovQualityChessAugust2013.pdf
https://www.chess.com/blog/smurfo/book-review-insanity-passion-and-addiction
http://www.nytimes.com/1988/09/26/books/books-of-the-times-when-the-child-chess-genius-becomes-the-pawn.html
https://www.forbes.com/sites/alexknapp/2017/05/05/making-a-living-in-chess-is-tough-but-the-internet-is-making-it-easier/#4284e4814850

https://www.chess.com/news/view/is-there-good-money-in-chess-1838
"... Many aspiring young chess players dream of one day becoming a grandmaster and a professional. ... But ... a profession must bring in at least a certain regular income even if one is not too demanding. ... The usual prize money in Open tournaments is meagre. ... The higher the prizes, the greater the competition. ... With a possibly not very high and irregular income for several decades the amount of money one can save for old age remains really modest. ... Anyone who wants to reach his maximum must concentrate totally on chess. That involves important compromises with or giving up on his education. ... it is a question of personal life planning and when deciding it is necessary to be fully conscious of the various possibilities, limitations and risks. ... a future professional must really love chess and ... be prepared to work very hard for it. ... It is all too frequent that a wrong evaluation is made of what a talented player can achieve. ... Most players have the potential for a certain level; once they have reached it they can only make further progress with a great effort. ... anyone who is unlikely to attain a high playing strength should on no account turn professional. ... Anyone who does not meet these top criteria can only try to earn his living with public appearances, chess publishing or activity as a trainer. But there is a lack of offers and these are not particularly well paid. For jobs which involve appearing in public, moreover, certain non-chess qualities are required. ... a relevant 'stage presence' and required sociability. ... All these jobs and existences, moreover, have hanging above them the sword of Damocles of general economic conditions. ... around [age] 40 chess players ... find that their performances are noticeably tailing off. ..." - from a 12 page chapter on becoming a chess professional in the book, Luther's Chess Reformation by GM Thomas Luther (2016)
http://www.qualitychess.co.uk/ebooks/LuthersChessReformation-excerpt.pdf