It’s not just billionaires.
I was from very poor parents.
I went to university on a scholarship (studying zoology and biochemistry).
In 1974 (having completed my undergrad biochem studies) it became obvious to me that radical life extension was possible.
Since then I have spent much of my time contemplating the sorts of attendant strategies that need to be present to reduce the risks from other dangers and make radical life extension work when the biological constraints are cracked.
It seems clear to me that market based values pose the single greatest risk to humanity, as markets undervalue abundance and over-value scarcity. Radical abundance has zero market value, but huge value to humanity if it is radical abundance of the essentials of human survival.
I am no billionaire, not even a millionaire, and I very much desire the elimination of all decreases in capacity associated with aging.