In any case, in the US the estate tax and the gift tax are basically the same thing, so rich people can give the same millions to their kids either before or after they die and pay basically the same taxes: https://www.cbo.gov/publication/57272
I was under the impression there's a large exemption for inheritances under a few million and then it's still a number lower than income tax on the rest.
Philosophically, you don't own anything after you're dead. Someone else, alive, is getting income in the form of an inheritance.