He has been in the NBA. He is getting paid to play basketball. He doesn’t need to entertain you to seek his dream.
Some people don’t want college. Some have realized that college is a waste of time in trying to get where they want to go.
I know a kid from Rochester that left college in his first year and wound up getting hired as a CEO of a start up company in Japan. At 19. He and the company realized he did not need a piece of paper to be successful. (Kid is a block-chain/encryption savant.)
OB is better off.
John Wallace did not really improve his draft stock after his FF run. Fans overrate that stuff for NBA draft stock.
Performance matters, (now he is doing it against pros, not people who will never go past college) but workouts matter as much, and sometimes more. Then there are background checks, interviews, etc.
There are also contract issues that have to be dealt with for roster sizes. He might be better than the 12th and 13th guy, but they have guarantees, and the agent might be friends with the GM or the agent has a guy they want to sign next year. For fringe guys like OB, there are a lot of things, other than talent, that go into making a roster.