Far more poignant in Buffet's case given his age and the length of time he's been in the game, and the sheer financial impact he has on the country. He's not a paper tiger.
Mr. Zuckerberg is exceptionally wealthy for his age, but he's young, and it's all based on a single assett. So while not judging, let's hold off on comparing the two for a couple of decades at least.