Buffett: Bill Gates and Jack Welch Got Out at the Top

I don't now how else to interpret this comment by Buffett, in his latest annual report:

....evaluations covering as long as a decade can be greatly distorted by foolishly high or low prices at the beginning or end of the measurement period. Steve Ballmer, of Microsoft, and Jeff Immelt, of GE, can tell you about that problem, suffering as they do from the nosebleed prices at which their stocks traded when they were handed the managerial baton.