Something John Isner's mom said the other day made me think of this thread. She said there were a lot of juniors who went pro while John went to college. Now he's top 10 or close to it and none of them made it.
With the game becoming so physical and guys doing better later in life, it's better to get your degree and compete straight after.
I guarantee Kosakowski will struggle in the lower levels until he can't afford to tour anymore (since it costs $140K on average to tour). He could go back to school later in life, but of course it won't be paid for.
Kind of a sad story.