I saw a comment on HN about this recently where someone suggested a 100% inheritance tax. I wonder what society would be like if we were able to implement this effectively.
The very wealthy would just hire their heirs as consultants or advisors and pay them exorbitant salaries. Sure, the government would take ~40% in taxes but that still better than losing 100% of it.
It would also push them to donate their fortunes to found private corporations and allow their heirs to "buy" the shares.
Or move their money offshore into assets that aren't readily convertible like real estate. How is the US government going to seize 10,000 acres of land in Brazil?
Unless you're prepared to enact Cold War era Soviet Union levels of control on all economic activity, the people who you most want to target will be able to side-step your plans.
Yachts seem to require a ton of skilled labor to build and maintain. I assume they provide for many solidly middle class jobs.