Why are the players better at 5/5 than at 10/0

I am rated 1700 at 10/0 (rapid) but 1250ish at 5/5 (blitz). And the other people around 1250 at 5/5 seem to be just as challenging as the 1700 level people at 10/0. I don't understand this. Does it have to do with the rating system? Why wouldn't I/we end up around the same rating for both rapid and blitz?

Ratings measure performance (history wins/losses/draws) rather than absolute skill in chess. So significant differences between your rapid and blitz could be due to one or more factors:

• The pool of people who play 5/5 may be very different from the pool of people who play 10/0. In this case, there's no particular reason to expect a strong correlation of the rapid and blitz ratings values for the relatively few people who play both.
• People who play 5/5 may on average be much stronger than people who play 10/0.
• You personally may play 10/0 much better than you play 5/5. (Using myself as an example, it's unusual for me to lose on time in a winning position, however in much more than a few 10/0 games I've been outplayed but have salvaged a win or draw with better time management. In 5/5, I would have lost many of those games I won/drew.)
• The 5/5 pool may share significant overlap with the 10/0 pool, but for some unknown reason(s) 5/5 ratings may be deflated relative to 10/0 ratings.

I'm not saying that some or all or any of these are the case, but they are factors to consider.

This is interesting. I never considered the pool of players would be different in 5/5. It's just weird. I don't really know where I stand anymore in the pack.

Also, do you think people win on time more in 10/0 or in 5/5?

I don't play 5/5, so I really can't really say. But I'd expect much, much, more losses on time in games without increments.

I think it all really just depends on the players. Certian players will play differently amd manage their time differently in the different time controls. For example, if your playing a 5/5 game and you have a slightly winning posistion, i know some peopkenthat will repeat checks for the sole purpose of gaining a little bit of time. Also in endgames if i know there is no increment, i might take a little longer in planning out hownim going to fibish the game say at 2 or 3 minute mark and then duringnthe last minite since ive already spent time ona strategy and gameplan play much much quicker in theblast minute and the opposing player who thought he was up on time becausr i took longer playing before will not have planned out his ens game and have to react to every nove and lose his time advantage and get conpletely frustrated and blunder in time crunch. Also flagging anf premoving, players who are good at this can use these to their advantages in both situations conpared to players who are not. I had a game recently where i was down to about 12 seconds and my opponent had  atleast double the time. There was no increment, and i premoved anf outplayed him making about 18 noves in 12 seconds while he was just moving his king around banking ob the fact that he could run out thebclock due to his time advantage, and i enses up matinflg him with 3 tenths of a second left. If you go to my page in one of my blog posts i posted a libk to that specific game. So i really think this is all just dependent on the players. I have also been in close games and tried to rub my players clock out in games with a second or 2 increment, gotten them down to under 2 seconds and i made a bunch of bad premoves to try and win on time and the person made good premoves and all of a sudden we both had 4o seconds on the clock up from under 2 and hehad a massively better posistion because my only thought was to try and win on time.

hmmm quite intriguing

hmmmmm

also my situation is completely concurrent with OP’s situation 

10|0 is a beginner time control, so there's that. But also 5|5 is an odd time control. (In my experience people who play odd time controls tend to be more experienced.) For example something like 0|1 and 0|2 on lichess is going to have fewer crappy players than 1|0 even though the games last about the same amount of time.

But anyway, you're saying there's a 500 point difference. I wouldn't expect that big. I'm not surprised there's a noticeable difference, but you're probably exaggerating it.

You can look at my game logs. I've been playing both the past few days. I am getting beat by 1200 players in 5/5. In 10/0, that simply wouldn't happen. I'm not saying that to brag either (not that it is even something to brag about) but this has got me doubting where I am in the pack.

Guess I need to rethink my whole life then.

nah I don't think so, they probably just prefer shorter time controls. 

blitz pool is significantly stronger than the rapid pool

Yea blitz pool is stronger. The bigger your elo, the smaller the difference tho. Just as important factor is the skill set of the player, some are better at fast time controls. Also I consider blitz a more casual format where I mess around more with sacs etc., this has an effect.

5+5 players are stronger than 10 min in chess.com , i feel that too