But then you take that person out of the "hood," and give him a $1M/yr sports contract, and the mentality doesn't necessarily go away. It's still about the hustle. They might not stop to consider that they don't NEED to hustle anymore. And they're probably also surrounded now by grifters/"friends"/family who do still need/want to hustle, and essentially using these guys.
It is sad.
I think the simpler answer is that some people are especially poor at risk vs reward analysis. Others enjoy the thrill of getting away with something. It's been 30+ years since Chauncey Billups has had to worry about money. I think your point about friends around them is very fair though. Lots of these guys have hangers on with their hands out and despite making lots of money in their careers they cant just give cash to everyone. So I can imagine them thinking "hey place a bet on my under for the next game because I'm going to go out early" seems like a low risk, not so evil way to put a few dollars in a friend's pocket.