On one hand, I think 'That person earned their money, they can spend it as they see fit. If the kids splurge it, it still gets distributed.'
On the other hand, I see how this makes it hard for life to seem fair. (But then again, some people are born attractive, tall, athletic, smart, etc. The upshot: life just isn't fair.)
Even if we agreed that high taxes on inherited wealth were proper, I doubt if it'd become law. The Kennedys, Bushes, Clintons, etc. wouldn't like it for obvious reasons.
I'm a fan of saying, first, that people did not earn their money past a certain point (my income has more than doubled since I entered tech and I am certainly not working more than twice as hard, I just joined a hedge fund instead of an unprofitable startup, and as a result I am firmly comfortable with any of these high tax brackets affecting me personally). Then you can say, we'll tax much more heavily at the point that you don't need the money to live. Then you simply don't accumulate the money needed for your children to live off passive income, and the question doesn't arise.
Also there is a difference between rich people and wealthy people. Wealthy people don't work hard, relatively speaking, per dollar earned.
But that's no reason to penalize the people who have done the work, followed the rules, played their cards well and had a little luck. They deserve to keep what they've earned.
Given they've done everything we could reasonably expect they should, let's make sure they are made whole with the amazing good fortune the winners have received by having everyone play an honest game.
We should work hard to strive for equality of opportunity.
We should avoid trying to guarantee equality of end result. (Because it's an impossible task.)
Summary: Everybody should get a fair shot. Everybody won't end up with equal results.
Everyone is not going to get a fair shot, since some will be born with more inherited capital (social, financial, etc...) . I'm not arguing everyone get equal results in the end. I'm suggesting that society will function better if folks are made whole. In other words, they have basic needs met and this standard increases with the increasing wealth of the country.