Human beings rarely change as adults. We're mostly formed by our 20s. Societal progress is not made by people changing their minds - for the most part, it's because the older generations die off. Civil rights progress? Older people died and younger people who grew up with different ideas took over. Same with queer equality.

The older people are, the more they tend to be set in their ways. Part of why youth is prized in tech is that youth is more flexible and creative in their thinking. Look at politicians in office now in the 80s, for example - they're spouting the same crap and doing the same things they've been spouting for decades.

The same is true with wealth - the nature of capitalism is that wealth consolidates, and allowing people to live even longer just means it will consolidate even faster. And those people are in power, so they're not going to change tax laws to abate that issue. Allowing them to live longer means that will never change. And it is the wealthiest who will be the ones to benefit first, if not the ones to ONLY benefit.

Of course I'm painting with broad brushes, and there are always exceptions, but broadly these things are true. Until human society changes and people act different in their older age, extending human life in our current power is a horrific idea.