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

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?