04and10 -- I'm not a coach but I can speculate on why the HS coaches stay put -- job security (to a degree) and $ (to a degree). Take home pay for most college assistants -- even in the visible programs -- won't take them home. And camp money is dispersed between a larger staff.
A few years ago, a TCU assistant took the head job at LMC in Jacksonville (D1 JUCO). Josh has worked his arse off to rebuild the program -- think "start from scratch" on the field, the roster, uniforms, etc. -- what a task! I think he has done a great job but the 2-yr programs are a constant uphill climb...roster turnover, a new D1 nearby drawing kids, east Texas challenges (no offense to anyone) --- many challenges. He dipped his toe in the college ranks. But, from my perspective, his life didn't get easier when he moved from HS to college assistant to JUCO coach. Coach Stewart provided my son with a place to play, against several whose names were called last week. Thanks, Coach.
High school baseball coaches have their own challenges, eh? (PARENTS, like me!)