That is, many people seek wealth, and signal it through a lack of frugality. Look at the number of owners of super and mega yachts, and tell me how they are frugal. There are a lot of such yachts, yes?
(You could say that they are frugal because they live well within their means, but that's not what you meant when you singled out Buffett and Kamprad.)
Look at billionaries like the Koch brothers, or the DeVos family. Money gives political power, and both of those families have used their wealth to push their respective political agendas.
Thing is, that can also be interpreted as "social/psychological signalling", could it not?
So it seems like anything that a rich person does can be interpreted as "social/psychological signalling".
I don't know what you refer to when you say "one billion people ... a trillion USD/year in value." Does that include all of the people who sing for free in their church choir, or who volunteer to organize a race, etc? Again, if you say those are all examples of "social/psychological signalling", then I think that definition is so broad as to be meaningless.
Much has been written about Carnegie's philantropy. Quoting Wikipedia, '"Maybe with the giving away of his money," commented biographer Joseph Wall, "he would justify what he had done to get that money."' Isn't that a rather different interpretation than yours?
Note too that Carnegie was far from frugal.
Finally, you reference to hunter-gatherer systems (excepting the settled hunter-gatherers) in what seems which reminds me of Marx's description of "primitive communism." If I continue with a Marxian analysis, those hunter-gatherer systems had no mechanism for capital accumulation, and it's that accumulation which contributes to the social power imbalance we see now.
How does "economic transparency", much less "apps running on personal computing devices" , result in a major equalization of social power gained from capital accumulation?