I mean, the main motivator for the endowment was always Malinda Gates. I’m sure it functions as a tax shelter, but I doubt that was really the main motivator. He’s already given over several times what his tax burden would have been, and if we compare it to other NGOs whose sole purpose is truly preserving or raising money, they really aren’t comparable.
I’m in agreement that no one should have hundreds of millions of dollars, let alone billions. We can discuss the validity of NGO as a concept, but as far as NGO go, the gates foundation has done more actual aid work for 3rd world countries than most governments.