SPY has a cumulative return of ~370% from start of 2000. BRK.B is at ~1,200%. That's a pretty big difference.
You can discount Apple as being part of the portfolio, but that's a bit like saying, well they wouldn't have done so well if we remove the high performing stocks in the portfolio.
You can discount Apple as being part of the portfolio, but that's a bit like saying, well they wouldn't have done so well if we remove the high performing stocks in the portfolio.