I agree with almost all of what you say -- BUT population itself does matter. The earth has a finite carrying capacity, even though we might not yet know exactly what it is There are strong indications that it has exceeded what it will be once one no longer has hydrocarbons for energy, chemicals, fertilizer and all else. There is some maximum sustainable population and sooner or later we'll have to find out what it is. Population control and reduction can be done by US via education, restraining reproduction, taking care of the elderly OR it can be done by NATURE via war and famine and pestilence.

The agricultural revolution, starting 10,000 years ago, occurred on a planet with thick forests and rich soils, although the stock of big mammals had already been considerably depleted by the hunter-gathering revolution of the preceding 50,000-100,000 (maybe more) years. At the end of the industrial age we will not be able to simply revert to one of the prior eras: the condition of the earth is no longer the same. Our involvement with the earth is going to have to be far more intimate and is going to involve carefully controlling our numbers and imprint as well, since we too are part of nature, not some alien force that can simply exploit it with abandon.