Well, if the time allows for another pursuit beyond all the regular day to day excitement, then a decent game of chess or a comfortable pair of shoes can't disapoint too much. Soooo I guess it's a low risk high gain sort of thing for one's ego.
Are chess players egoistic nerds?

Being able to play chess, read books, etc., is a luxury that at least 1/3 of the world cannot have.
That's not even close to being true.

Why are people doing things they do everyday? Why did you just write this post? Why are we here? Why do we ask questions? After reading the first sentence I decided not to read anymore. I am pretty sure if you seek a serious answer you would ask yourself..

Not that it isn't obvious, but I am pretty sure it was what is known as a "rhetorical question". Good thing you do your research and due diligence before jumping to conclusions.
What really motivates chess players? How does it go from being just moving a bunch of objects around some squares with arbitrary iteratively contrived rules, to something people take so extremely seriously, and consider a true archetype, a sacred cow, as it were?
There are no doubt many self-assured cerberal lucid and subjectively objective players, who might even consider themselves atheists, that unconciously deify chess (and to the degree addiction doesn't explain it, their inevitable defensiveness regarding chess likely does).
And, you can't just say it's the intellectual love of puzzles, challenges, or complexity, because if that were the sole motive, one could find infinite challenge, even a chance to improve the world, by becoming a research scientist, inventor, or working on some of the difficult ugent problems facing the planet.
Therefore, it seems that chess players have a lot to prove. But is chess the best way to do it? Difficult and time-consuming as chess can be, for all the hard work involved, in some ways it is just another convenient, self-serving a lazy pursuit, which could be likened to creating impressive new styles for a comfortable old shoe.