That is true to some extent, but I'd argue that there are diminishing returns on this. That is to say that ambitions would certainly be greater if we had more time, but I don't think it'd scale linearly.
Another way to look at it would be -- How much more stressful would our lives be if the average lifespan was 40 years instead of 70+?
I don’t think your question can be truly answered, but as a thought experiment, do you suppose the average person 200 years ago experienced more, less, or the same amount of stress that we do?
It’s tempting to say less, since they arguably had “simpler lives.” But it’s also easy to say “more,” since they had a much more present risk of death than we do.
My hunch is that stress is (mostly) relative, and that (outside of trauma) how much one experiences is determined more by ones worldview than ones circumstances.
Another way to look at it would be -- How much more stressful would our lives be if the average lifespan was 40 years instead of 70+?