Berkshire has outperformed Nasdaq and SP500 from the IPO (May 9, 1996), 10y, 5y, 1y time periods and he has now $340B in cash.
All this with low risk holding lots of cash. He has not missed anything.
Just because it beat indexes doesn't mean it couldn't have done better.
From 2017:
https://www.cnbc.com/2017/05/06/warren-buffett-admits-he-mad...
His only miss was actually buying Berkshire. He estimates that he lost out on well over $200B had he never bought Berkshire.