Another good idea, IMHO, is a thresholded 100% tax (e.g, after 2M per heir, excluding main résidence), everything is put in a sovereign fund. Basically the same effect, but doesn't touch smaller inheritances and family house.
Why not just the top bracket of income tax at 100%?
This however is just a launching point for a discussion about how what you or the ex-CEO are proposing in that tweet makes you an enemy of the human race and likely to be the first against the wall when the libertarian version of The Purge begins.