slightly more philanthropic than the rest of the world which makes sense given how prosperous the US is, but overall US billionaires actually do not give much and Gates and Buffet are indeed outliers. The average billionaire donates barely more than the small fraction of a per cent annually. The average top 20 billionaire does in fact give less relatively speaking than the average American household.
https://twitter.com/gabriel_zucman/status/119842279460784537...
Survivorship bias.
A generous billionaire.
Those that don't are just greedy billionaires.
[0] http://worldpopulationreview.com/countries/life-expectancy-b...
https://www.sciencedaily.com/releases/2016/10/161013103132.h...
Life expectancy loss is mostly drugs and obesity. Hard to see how philanthropic billionaires are a problem on either front.
Asian Americans have a life expectancy of almost 87 years, longer than in any Asian country. Hispanic Americans have a life expectancy of almost 83 years, exceeded only by the richest Asian countries (Japan, Singapore, Macau) and Monaco and Iceland.
The difference is that do not trust the government to know what's best nor, do what's best.
US billionaires are only philantropic because they don't want to end up either dead or stripped off of all their assets when there is any kind of revolution - no matter if a "real" revolution or an elected one, e.g. if Warren or Sanders win in 2020.
How much of his wealth does Bill Gates spend on the military industrial complex?
It's the same problem that Europe has with its defense - we have over decades relied on the US to keep us safe, without contributing our fair share.
As you put it, if there was some kind of "richness cap" (say, 1 billion) and all the rest was held as interest generator for social services and society, population wouldn't have to depend on the "goodwill" of people, but would have the basic necessities fulfilled.
Humanity will get there at some point. There is no other alternative, given population growth. But right now we humans are still quite underdeveloped as a society.
I feel that was expressing a desire for more transformative change over fixing the individual problems we have now. Change the world so much that the problems are no longer an issue.