I'm still playing emps-world, so i'm never gonna quit playing.
But, some reasons why a person would quit in my view.
First, the economy:
all these prices are insane compared to emps-scape. You see items that are 10x more worth then before and items that are 10x less worth, it all doesn't makes sense anymore. I know World just came back and the idea of removing all the banks to give all the players the same fairness, but you should spawn some cash or items give them to some random people to make these prices as they were, and with this i don't mean giving items to the usual people who get them first (if you've ever done this before, i dont know), but giving them to even the most newest players, it'll give the small players a huge chance to decide in the ongoing economy, compared to the usual richer get rich and the poor get rich eventually (but cant do as much impact on the eco then the big players)
Second the bugs/glitches etc:
i'm seeing a lot of people complaining about this that they lost their items, of which they really have worked hard for to get. it's always the hardest in the beginning, this only makes it worse.
Third, client problem:
As you said before, some players have problems running a client, so they cant even begin to play (like me, but i still got hope). Coming back here, and being so happy that you can finally play emps again, and then seeing you cant even run the client or load the cache (personal client problem there), so why would you then even stay here?
finally, the combat system/item stats:
I'm seeing that a lot of items still don't have logical stats as everyone is complaining about, but this is more of a problem that gets done over time, just have patience, some people just don't have it and when they see something that's not right, they immediatly leave.