However dubious, theoretical, or inapplicable to the real world the study might be - it does sound well-designed to appeal to narcissistic billionaires. And the author of the study appears to be a not-yet-tenured professor at an American university...
Having reached the plateau I can tell you that the confidence you had that you would probably live on is replaced by genuinely not knowing if you have 3 years or 30 years left. It is disconcerting.
https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2022/...