I'm not sure that's the truth though. Much of the burden on the ecosystem from over population comes from the industrial/tech/consumption part of the equation which only a billion or so really benefits from, not necessarily the total head count. Further, how many resources are withheld from the population by a few? I think the whole over-population thing is either an exaggeration, is based on the first world's tech taking over the whole world, and lastly, could be taken care of within several generations voluntarily (I don't have kids, I made that choice)--and I concede that last one is sketchy, unlikely, but not out of the realm of possibility.
Your second paragraph reads to me as supporting a minimum technological society, not against it.
Once again, I'm not sure we have to assume that the future in all it's possible courses (and I hold there is more than one) are dependent upon the maintenance of today's political environment, and will, in fact, unfold in spite of it.
Perhaps, AI if it evolves... it will sort all of our problems out for us...but I'd rather we do it ourselves, like responsible grownups with the idea of leaving a better world for those who come later, not an ever-worsening cycle of same old, same old...until nothing can live here. But, that's just me.
Long term, I think you're right. It's the short term that's going to be extremely painful for a large portion of that seven billion. Although by short term, I'm speaking decades, not years. I think an economically sane world is the only one that has any chance of supporting the population levels we see today, and more.
That means the politically-induced misallocations that keep billions poor and a relative few who are politically well-connected massively rich (in paper assets) have to shake themselves out. I suspect that realignment won't happen without a lot of pain, but I have no doubt it will happen.
The productive class could maintain a healthy planet with a population equal to or exceeding what the world supports today. OTOH, no business, country or planet can afford the massive overhead, restrictions and misallocation that the political class represents. Look at the condition of those countries with the most powerful political classes, and the conditions we see here as the political class grows in power, and it's not hard to see what that overhead does to productivity and innovation.
The ascendency of the political class invariably leads to the benefit of the few at the expense of the many. See also: North Korea, Cuba and the history of despotic rulers throughout history, and contrast it with the massive explosion of innovation and productivity that was unleashed when one country, for a brief time, broke free of the boundaries dictated by a small group of the politically-privileged.
Thankfully, the internet has come along and created a new place, outside the tight control of rulers, where that level of innovation is once again possible... and I don't believe the ruling class can stuff that particular genie back in its bottle.
Long term, history is the story of the political class losing its grasp on the productive class. Long term, the political class loses. It's just a matter of time; I'd guess decades at the most.
Or, as you said:
Once again, I'm not sure we have to assume that the future in all it's possible courses (and I hold there is more than one) are dependent upon the maintenance of today's political environment, and will, in fact, unfold in spite of it.
The battle today is between a resurgence of The Enlightenment and a return to the Dark Ages. I'm betting on The Enlightenment in the long run, although there may be some Dark Ages ahead.