Then you have the "surfeit of princes" problem.
This isn't just grand political power: imagine being unable to progress in your career because geriatrics above you aren't retiring.
That's just one possible secondary effect. We could enumerate many others.
Just to be clear: I'm not from the US, we do have not a very good but nevertheless somewhat working public health system over here.
In the US, we just will do neither for the majority of Americans. If you're too poor to afford rejuvenation, you'll be too poor to afford other treatments. And you'll just die.
Sure the cost of each treatment might be pennies (although it probably will cost a lot and not have those economies of scale) but total profit is not maximized by a smaller markup. Better to get Gates/Bezos/Musk/other billionaires to give you 90% of their fortunes.
Except those people are more likely to be too poor to afford it instead of unwilling to take it.