Sure, but again to your own point, the share of voting Americans who don't earn income (and therefore pay no taxes) because they are over 65 is already 1/3 and only going to increase.[0]
There will always be zero tax payers with the right to vote.
That's OK, especially since most of those who are now over 65 and retired worked and voted on reps/platforms/policies from 18-65 and earned income/paid taxes for probably ~40 of those years.
[0]https://www.kff.org/other/state-indicator/number-of-individu...