67 Billion dollars speaks for itself. Yes, I think that methods of investing have forever changed, and for the average investor, buying and holding is difficult and sometimes not prudent. The advantage Buffett has is the best knowledge, information, and resources to make a decision. Buffett can buy the entire company, sit on the board, and make decisions. The average investor cannot hold through a pullback, recession, or depression the way Buffett can.
Let's not forget that Buffett owned Fannie Mae until 2000/2001 when he saw lending standards loosen and sub prime mortgage applications rise, when he sold he shares. He suggests average investors buy index funds because there is no way they can beat the market. This is probably true, however, a more modern portfolio, in my opinion will consist of index funds, high dividend yield stocks, growth stocks, TIPS, treasuries, Alt-A Assets such as managed futures or portfolios such as The Endowment Fund, which is heavy in Alt-A including hedge funds, and commodities, such as gold. 60%-40% stocks and bonds is a thing of the past , but for someone with the buying and holding power of Buffett, it will work because the time horizon is not only so long, but also doable.