I was going backwards in the thread and seeing this peaked my interest (and spiked my cortisol) so I did some jestergoogling:
The percentage of americans over the age of 70 in 1989 was between 8% and 8.5%, the percentage of americans over the age of 70 in 2024 was 12% to 13%.
This means that almost all of the disparity is caused by population change rather than them becoming richer,
8% to 12.5% means an increase of 56% in the 70+ years old population.
19/100 = 0,19. (meaning each percentage of population increase in the +70 age group corresponds to 0.19% more of the total wealth)
0.19 x 56 = 10,64% percentage increase in total wealth just by population increase with the wealth remaining constant.
19% + 10,64% = 29,64%. Only 2,5% is them becoming richer per capita.