Blah blah Mark Zuckerberg never graduated from college and he did well, so I guess we should all drop out?
It's a massive disservice and idiotic to claim the exception as the rule.
And you clearly don't know crap if you think diet and proper cross-training are critical in taking you to that next level. Poor diet = poor workouts and most importantly, poor recovery for your next workout. Same goes with cross-training. If you don't have a solid strength training program (and I don't mean just weights, I mean plyometrics and other biomechanical training), not only do you greatly increase your chance of injury, but you're also missing out on the development of key muscle groups that will increase your ability to run faster for longer without injuring yourself. Go to any D1 program and you'll see that the athletes spend just as much, IF NOT MORE time doing cross-training than actual time spent running. A standard 10 mile run can be knocked out in about 1 hour. Time spent stretching, doing plyos and weights will easily take up over an hour each day.
"Oh but the Kenyans don't cross-train!" You're right, they really don't. But guess what? The vast majority of the Kenyans in the youth training pipeline end up injured and their careers cut short even before they hit maturity. Why is this? Because they lack the resources to implement a solid cross-training program so it becomes a game of "survival of the least-injury prone." It's a sad reality.
You yourself say, "you can get 90-99%" of the way on your own. Maybe true, but at the top level, you should know that "1-10%" improvement is huge in running.
When you're tired, exhausted, legs are shot, hungry, have classes and homework to do...oh but you have a tough track workout scheduled. What do you do when you're on your own? Maybe you'll go for a jog, or maybe you'll rest. But if you're on a team with motivated and hungry runners, guess what you'll be on the track hauling sass. Having teammates is crucial not just for pacing, but also motivation. Who wants to get up at 6am for a morning 7 mile jog when you're beat from yesterday's training? And who can do this every single day of the year on their own? Very few people are that motivated.
Guys who never trained at the top level and have a chip on their shoulder should stay out of threads about training in college. Thanks.