E.g., someone in poverty today isn't particularly comforted by knowing they have luxuries that former kings didn't have, like plumbing, because well-being is tied to relative scales
It is objectively better to not have to go out in the cold to take a shit at night, even if you're "poor".
Consider that fact that at one point in the past you probably thought what you have now would make you happy. And maybe for a short time you were. But invariably that feeling of well-being wanes. You can say your new car is objectively better than your old one, yet after having it a few years it feels exactly like the previous vehicle from the standpoint about how much it contributes to your well-being. If well-being were an objective fact, you'd still feel happier with the new car. Most of the time, we have an innate ability to shift the goalposts, which keeps us continuously striving. To that extent, well-being is all subjective. I'm sure people in 200 years will wonder how we ever got along with our miserable existence without the creature comforts they take for granted.
I agree with your point on human psychology, but survivorship bias is relevant here.
One way in which my new car is objectively better is that it has better safety features, which makes me less likely to die in a crash. My feelings about it may well normalize over time, but only if I survive long enough.
The correlation is not perfect, but lots of creature comforts actively make us live longer. In addition to the comfort of pooping indoors, indoor plumbing also makes it easier to wash your hands with warm water afterward, harder to trip and fall on the trip to the outhouse, both of which make you live longer. The people who die don't get to psychologically adjust to their premature deaths.
It doesn't have to be either/or: make something cool, throw out a link to it, repeat.
