As I said in a other comment, I think “they didn’t live long enough” is a bit of misconception. I’ll repeat my comment here rather than writing it out again:

"So I’m no expert, so take this with a grain of salt, but it’s my understanding that while average ages were much lower in the past, this number is heavily skewed by infant mortalities and deaths due to preventable disease. As I understand it, the expected age of an otherwise healthy individual was pretty comparable to us today. More people died young, but those who didn’t lived about as long as us. So I don’t think not living long enough for skin cancer to take effect really jives with my understanding of history.

But again, I’m not an expert and the likelihood that I’m just an idiot who is wildly misunderstanding things is, frankly, high."