consistently show that roughly 70% of wealthy families lose their fortune by the second generation, and a staggering 90% lose it by the third.

You could look on the bright side

This isn't what one wants for one's own family, but it's a good trend for the world: nobody wants to live in a society of fixed dynastic wealth, where you have (or do not have) lots of assets through the luck of what your great-great-great...grandfather did (or didn't do).

The UK had a lot of this, and worked hard to squeeze it out of the system by having high (lately 40%, down from ~80%) inheritance tax for the last 80 years, which has worked to a reasonable degree. The US has gone the other way, with rules to allow creating of new dynasties that seem likely to continue for the next century. (that's about the top few--US income quintile mobility is low, but contrary to popular belief hasn't really changed in a long time)

Of course, it's a genetic imperative to provide as much as you can for one's children. I can see that, so I favour zero inheritance tax on passing wealth to your kids. But I also favour a very large tax on your estate based on however much you inherited during your own lifetime, so generationally it's a "one and done". If you want your kids to be rich, fair enough, but make the money yourself.

Jim