From my experience, I think coaches are idiots because they don't seem to care about the team and they care about themselves.
I had a coach in my first 2 years in HS that cared about his son. His son was fast, but he was trying to get his son a running scholarship to Stanford. When I look back into this, I realize that not only he wants his son to get that scholarship, he wants to make sure he and his son are not forgotten. I ran in college and boy that guy is hella salty. That guy is so selfish that people who loved him got hella selfish or had selfish moments.
My junior year XC season, I had a coach who's also selfish. He was in it because he just wanted to brag to the whole world that he's coaching (Most HS coaches do that). He overtrained us and made tons of selfish decisions. Example: He wanted to run a steep hill route the day after a race because he wanted to. At the end of the season, I had a fallout with him. The team also got him fired. Pretty sure he's salty about me running in college.
In college, I had a coach who was in it to say "Oh I get to coach at my alma mater". However, I got lucky and was able to improve by a lot. He ended up getting fired, but I still respect the guy.
My other point is there coaches out there who have anti athletic views. They are against having their athletes and even their kids run in college because they think these athletes can use that time for their academics. Why discourage the kid from accomplishing their dreams? Also, I can't be studying all the time.
Junior year track season, I had a coach like that. My dad was telling him about how he disapproves me running in college and the coach was agreeing with him. Btw, my dad gave into me running in college.
No matter what level, a good team must have a good top. So in HS and college, a GOOD AD.
So again, coaches are idiots because there are coaches who are selfish and there are coaches who have anti-athlete views.