Climate catastrophe is expected to destabilize societies. A natural outcome from that could plausibly be the rise of extreme ideologies that advocate for nuclear conflict for example. It’s plausible human beings face an existential threat in the coming decades.

I think human progress is a chaotic process dependent on human choices, not a determined one. For example some hunter gatherer societies have lived lives of leisure working as little as 15-20 hours per week - quite a lot of ease compared to the modern work week most of us see. Human history is much more heterogenous and chaotic than what one might conclude from a perspective limited to today, medieval peasants, and ancient Egypt.

Luxuries I think should be viewed critically also. The effect of luxuries is unfortunately likely canceled by the hedonic treadmill. In our current society roughly 30% of people are suffering from mental illness like anxiety or depression. This is despite having iPhones instead of landlines.

You are right that longevity has increased over the long term. I think this is a stronger area of your argument. But is longevity alone a good measure for quality of life? I think we should include other factors, like happiness. Unfortunately we just don’t have those statistics over any meaningful horizon.

Overall I think measuring quality of life over the long history of our species isn’t quite as straightforward as you make it out to be. We must be wary of adopting just so stories. Quite a lot of heterogeneous human experience falls under this generalization, and most of it, at the very least, we just don’t have good data for.

In my view, progress that human beings experience is contingent, the result of our choices. Sadly I don’t think there is an arrow of history that guarantees a better future for our species. The risks we face in the upcoming years are immense. If there is a better future waiting for us, I believe it’s one we will have to fashion ourselves. Relying on an abstract concept like the arrow of progress can even be dangerous if it misleads us into forsaking our agency in fashioning our collective future.