The wealthy don't stay that way by keeping tech secret, they stay that way by selling it to everybody else.

This is actually the main plot in Orson Scott Card's "Worthing Saga", although I've seen the concept explored in Peter F. Hamilton's Commonwealth series and Richard Morgan's Takashi Kovacs novels.

It's a fascinating concept to think about, and frankly depressing because it feels uncomfortably close to the reality we're headed towards.

This is my concern too. Sure, I'm not a huge fan of the idea of myself dying someday, old and decrepit. But there are a ton of people out there about whom it gives me some relief to remember that they too will die. And most of them are the kind of people who whold have first access to anti-aging treatments.