It isn't just aging.

Americans are spending a lot more on quality-of-life medical interventions, many of which are outside the normal standard of care that would be covered by healthcare systems. It is a booming business in the US and many people seem to have no trouble paying for it.

It's like the hydration revolution, wealthy Americans (or those who aspire to be) are very conscious about their health/career/investments/childcare/looks. Many of them seem quite neurotic, maybe it's a consequence of individualism and social media. I don't think it's something which is unique to the US but they're just ahead/rich compared to other countries.