I was actually curious based on the graph you posted what regions were strongest for producing top-level basketball players. I looked at # of NBA players produced for each state, then looked at the population of each state and ranked them according to "Population Per NBA Player Produced", then combined into regions. Here it is:
As expected, the Midwest is best at producing NBA players, followed by the Pacific region, Northeast, and South (all very close together), with the Plains/Mountain West states bringing up the bottom. FYI, I included Texas in the Plains states. Interestingly, outside of the Plains states, the other regions produce pretty close to the same amount of NBA talent.
Cool idea, I'd like to see the data split with these divisions. Not saying you divided them wrong, but this is how I think of the US being divided. Either way, the outcome probably doesn't change too much, I can see the Southwest being the third though.