Look at this list of schools that are Division I basketball:
http://sports.espn.go.com/ncb/teams
I realize that some of these may not have DI track teams, but still. How many schools can you name in these conferences: America East, Atlantic 10, Atlantic Sun, Big Sky, Big South, Big West, Colonial, Conference USA, Horizon, MAAC, Mid-American, MEAC, Missouri Valley, Mountain West, Northeast, Ohio Valley, Patriot League, Southern, Southland, SWAC, Summit League, Sun Belt, West Coast, WAC.
Unless you're in the conference, not more than a handful. For every Northern Arizona on here that will have national caliber runners, you're going to have Eastern Washington, Idaho State, Montana, Montana State, Northern Colorado, Portland State, Sacramento State, and Weber State rounding out the conference. I'm sure there are some individual standouts somewhere among those schools, but I've never heard of them.
The average DI runner is probably as good as an above average high school runner.