Like cynicalkane alluded, Buffett donated tens of billions to the Bill and Melinda Gates Foundation -- he didn't even create his own eponymous foundation! He did, if I recall correctly, set up a foundation in his wife's name, and that may well be how he transfers some wealth to his children. But at the end of the day, he could have made them each multi-billionaires, and he chose not to. In a small way (with a few hundred million or a billion dollars), he didn't put his money where his mouth was. In a much larger way, to the tune of tens of billions, however, he did.
No. Warren Buffet's son was on NPR maybe 2 months ago, he'd written some music or something. He makes his living as a musician. And it was explained that his dad arranged things so that the kids all have to earn their own livings. Apparently, the son is fine with that. He sounded like a really nice guy.
That's now. If he fails, do you really think that the foundation won't take care of him?
FWIW, it's interesting to me that no one commented on how Buffet makes money from the estate tax via his insurance biz. He sells a line of products that only make sense if the estate tax exists.
In most cases, folks would say "look what we found when we followed the money". Why is Buffet and the estate tax different?