looks like injury problems are to blame for the move coupled with "personal" issues. so you move down the road.
you might conclude that salazar is injuring his athletes with his experimenting and "novel" techniques.
then again, you have webb, wheating, fernandez, solinsky all injured, it looks like at any given moment, 30-40% of the best runners are injured or coming back.
needless to say, coaches need to get better at keeping athletes healthy. probably it is a long term problem, things like diet may factor in greatly. tendons, bones, muscles tear need to be strong, you need to be eating well for most of your life.
suddenly going vegetarian or going on a some other kind of crack pot diet will not suddenly fix many years of dietary mistakes.