You'd still get regional overpopulation issues. E.g. the Justinian plague in 541 AD. That's still far away from mobile hunter gatherer tribes with densities of a few dozen people per 1-100 km^2.

Homo sapiens is 300,000 years old, Homo erectus 2 million years. Modern civilization might not last on the order of 10,000 years, industrial civilization maybe not even 500 - or perhaps "forever", if we make it to controllable runaway technological improvement?

We have more forests today in Europe than we did 400 years ago.