what you say about conditions is true. but the same conditions also exist for a whole bunch of other races all around the world. Go to India, Malaysia, Singapore, Thailand, China, any country in the Middle East or Russia just for a few examples. pretty much anywhere in the world except Northern Europe and you can replicate the same conditions you are talking about. But do urban Indians and Chinese in tough conditions take the easy way out as often % wise. I would say not.
I've met quite a few dedicated blacks Americans in my life, but I actually think you've got the more racist opinion here. There's nothing stopping the majority of the blacks from working hard 9 to 5 job as opposed to elite athletes. You've already pigeonholed them into the famous ones who are athletes only, boxers, track and field or entertainers. There are plenty that do become doctors, managers, teachers, accountants, graphic designers etc... but too many black males as a % of their own black population just don't bother. The black women in general are much harder working.