Really all chess.com needs do is have it so the game is automatically forfeit if the user is disconnected for longer than 1 minute. You cannot punish people for being sore losers. You still got the win, regardless of how poorly your opponent handles it.
abandoning live games

I'd say if Chess.com made live chess Premium Members only feature, then the amount of stallers will decrease alot.

How is chess.com supposed to differentiate between "sore losers" and people who get disconnected because of PC, browser and/or ISP problems?

It is no use differentiating. That is why any disconnection should be ruled an automatic forfeit, a la FICS.
That works for me...I'm not the one worried about punishing sore losers they're already being punished with a miserable attitude that fosters anger, discontentment, bad karma, etc.
BTW how's life on the Ponderosa these days?

Quit whinin, grow up and deal with it. Nobody plays real chess here anyway
Excuse me, but some of us TRY to...

I don't think it's automatic in FICS - there is a noescape variable that can be optionally set or turned off.
It would be great to have something similar here, controllable by the players involved in a game. I've watched a number of long time control games recently that were unfortunately cut short due to brief unintentional disconnects, even though both players would have preferred to have had an option to keep going...
Seriously chess.com. do something to stop or punish sore losers that abandon their game when they lose. Telling them they suck and have no honor doesnt do it. Even telling them I can hear their crys and feel their tears around the earth doesnt work. I can hardly believe that myself!
So punish these punks because they ruin the game!