Your criticism is that there isn't a foul-proof way for the rich to stay rich forever?

Of course there are going to be major hurdles during total war and extreme regime change. That would be obvious to anyone who wasn't being disingenuous or thick-headed, or both.

Those circumstances have nothing to do with this discussion as its not a realistic threat for billionaires of today, especially in America.

The 2007-2010 crisis did not impact the billionaires. They are still billionaires.