If you were to summarize Buffett's investment philosophy in a few sentences, it would be that he found a long-term sustainable strategy and method early on, and then integrated knowledge with action, practicing it throughout his life. It's not mysterious and is even a bit dull.
The reasons most people cannot achieve his rate of return are:
First, there are many temptations in investing, with stock gods everywhere and limit ups all around;
Second, when the strategy doesn't work against the wind, they drift and cannot persist;
Third, they buy a bad model or bad stock thinking it's Coke and persist long-term;
Fourth, they buy at a high price because everyone says it's good, and they also buy it;
Fifth, they sell too early.