It's really important to know what level of athletes your coaching and what the environment in the school is like.
Perhaps the one thing I've learned from coaching HS kids over the last 7 years is that a good coach for a team isn't always a good coach for getting the most out of every runner. Knowing the finer points of periodization, etc. is necessary to really develop good runners over a long period of time, but that has little to do with getting good results on a high school team.
The best high school coaches have two things, one they bring, the other they inherit:
1. A school with enough kids who will run instead of play another sport, and when they run will be dedicated (INHERITED)
2. An ability to influence kids to work hard and an ability to build a culture where kids WANT to work hard and do well (BROUGHT)... which more or less translates into not jogging around every day but really RUNNING either LONG or FAST.
Without both of those things you won't coach great high school teams.
I think another way to think of it is this:
The margin of return you get on smart training is important to coach great individual runners. But you can still get 80% of the way there with just hard training, not necessarily smart training. Furthermore, there's little benefit to smart training if the kids never work hard. And in a sport like XC, you want a high mean and a low standard deviation to win meets. A good way to accomplish that is to have a lot of kids work hard together and beat each other up every day. It's hard to accomplish that with the long view, smart approach to training -- most HS kids aren't focused enough for that. They don't get it. They do understand "RUN HARD AND YOU WILL IMPROVE."
I'm in my head a lot thinking about this or that better way of training. I've had some pretty good individual results that I attribute to reading, seeking advice from smarter people than me, and really working closely with the few athletes on my small team who really want to train hard and get it right. That's rewarding. But no matter how smart I train my top guys, my team will get trounced by larger schools with kids who go out and run hard and/or long several times a week.
Those teams usually don't send a lot of kids to college. But they do well in HS, which is what the kids want, what the principal/athletic director wants, what parents want, and what the coaches typically want. If your jacka** friends have a way to motivate kids to run fast and long, a lot, they'll make solid high school coaches.
I have little insight into college coaching. Totally different to work with athletes who nearly all care about the sport and doing well.