it is actually easy to figure "high" and "low", based on price vs value of a certain stock. Warren Buffet has been doing it for a while. most people don't have that discipline and prefer momentum.
Correct me if I'm wrong but wasn't Warren Buffett an activist investor who'd find undervalued stocks from companies that had poor management and, once his partnerships gained enough control, fire the current management and replace it? Sounds like a far cry from "buy low, sell high".