That is misleading. Infant mortality was high, but for those who lived past childhood average lifespan was not that far off from what it is today. https://condensedscience.wordpress.com/2011/06/28/life-expec...

What you said is also misleading. Hunter gatherers could live as long as people live today, but they frequently did not. Murder rates among hunter gatherers are insanely high. And there are all manner of disease that are no longer fatal, but once were. Heck, I've had several infections in my own life that would have been catastrophic 100 years ago.

OK. they only had a 50% chance of making it to 5 years old. That's much better!