Because it's the best console on the market, simple as that.
Hardware wise, it's the best out of the 3.
And for the games, they have the third-party (same as Ms, not for Nintendo), first party (very great on nintendo, but Ms...) and japaneses games (not on nintendo, not on xbox, because obvious reasons) + indies who missed on ps3.
But what i said here is only for people who play a lot, so generally , it's mostly because :
It's THE playstation.








