Even if we can’t push the maximum human lifespan past 120 or thereabouts, if we maximize the quality of those 120 years that would be an enormous boon to mankind.
It’s not just that more people are living longer, they are also living better. Yes, we have chronic, on-going conditions and issues, but we can do something about conditions that a couple hundred years ago were completely untreatable and added considerable suffering to the human condition.
There was a thread some time back about Dopers who, without modern medicine, would be dead by now. Find it and read it (and yes, I am one of them, too). It’s both enlightening and disturbing.
My parents just moved into a very nice senior living facility - they have a nursing home and rehab suite and dementia ward on the campus but the part my folks live in is independent living, sort of apartment style where everybody has a kitchen but nobody uses it. So we meet a lot of other residents in the dining areas and such. (Well, “we”. They hardly notice me. My baby, however, is the damned place’s mascot.) Anyway, so these people are self-selected for good health and mental acuity, of course. But I’ve been shocked at what good shape they’re all in. A lot of them use scooters and such - they’re doing a lot of construction and they’re trying to build in a LOT more scooter parking for the new areas - but I’m consistently amazed to find out after some lady passive aggressively tells my son that he needs to have socks on that she’s 95. I sat next to a centenarian once and chatted for a whole lunch assuming she was somewhere in her 80’s! And of course my mom is 73 and you’d never know it. The people who make it to advanced age in decent health are definitely living better these days.
I often think about how shitty it would have been to be like my dad even thirty years ago - he has herniated discs in his back and some mobility problems from a stroke, so as he gets older (he’s 83) he needs a walker at home and a scooter to get around the facility. But he’s got those things, so he goes to swimming classes, he goes to yoga (seriously! I cannot believe my dad is totally into the yoga classes now that they’ve moved to this place!), he goes to men’s bible study, etc. Just a few years ago he’d have been limited to the walker. A few years before that probably he’d be stuck in a wheelchair or in bed and probably he’d have died by now of all the things you get with immobility. Just considering what the ADA has done to make it possible for people to remain mobile and independent - wheelchair ramps alone have probably extended people’s lives.