The bigger question is what happened to Omaha and, to a lesser extent, Lincoln now that its population is around 200-250k. Some interesting theories out there, some of them pretty controversial. North Omaha used to produce very good players regularly, but they've all but disappeared over the last 20 years. even the burbs, like Bellevue, could produce some quality talent. But it just seems dried up. I'm guessing it's a combination of declining support in poorer school districts (North Omaha) combined with development issues vis a vis suburban schools where hoops might be a 2d or 3rd sport instead of a primary.
When South Sioux City seems to be your best breeding ground, you have issues.