"I get the impression that the "inequity" people think we should prefer the 1970s, because at least then, even though we were all sicker, no one was 10,000x healthier."
Except that in order to become healthier, you don't have to take someone else's health away.
I think a better analogy would be something like that (stupid) movie In Time, where people are given a certain amount of time to live when they turn 25. They can freely trade that time with others. Some wind up with millions of years of time, while the majority are cheated, exploited, and misled by the wealthy ("time is money") and face the risk of death at any moment as they scramble over what little time they have left.
As weak and flawed as the movie is, they're right about one thing: it doesn't have to be that way.