If YOU get a broom and I get a broom then we can be Broom-mates...... and sweep together.
Running well is NOT rocket science, dudes & belles. FIRST you have to get yourself into decent running condition. It takes time and a LOT of long lonely running. It is almost a self-imposed isolation. You CAN do that part but most people are not willing to pay the price.
Then you have to understand your competition. You don't have to be the fastest runner to win the race. If you can make everyone THINK you are wonderwoman or superman you can beat great runners. If you take the pace out too fast you are wonderwoman/superman. If you stay near the front for 2/3's of the race and then throw in a monster sprint, you are superman/wonderwoman. If you can hang with the leaders and then start the finishing sprint way too soon, you are wonderwoman/superman.
What I am trying to instil in the uninitiated is that even YOU can become an XC wonderperson! YOU!
In my days there were sports scientists too. They told us not to start distance running until you are at least 24 years old. They told us to take plenty of salt. Same scientists; new guesses.