That is not what I posted - I posted that we need to learn to voluntarily control ourselves. If we can't do that - evolve from a species that solves its overcrowding problems by going somewhere else, (as most species are biologically programmed to do) to one that is smart enough to not need to go somewhere else, then we are probably doomed to a drastic population crash and doom our hopes for space travel. We can't move people off the planet faster than people can reproduce. And, even if we could, people will also reproduce in whatever locations they move to, and overpopulate those locations too - unless people learn to stay within the "carrying capacity" of their locations, on Earth and elsewhere, too.
Yes, overcrowding has driven scientific advances, many in destructive device capabilities that then get turned to some constructive purposes, too. And, if everybody lived a happy life with no conflicts, that might slow technological advancement, too. It is not a one-issue situation - it is a balancing act.
I like your thought UE, but it narrows down finally to one, single, issue. As Hawking foresaw, and many of us have foreseen, birth out of Earth or die. You don't talk any individual, UE, talk the cellular lot of Mankind! As Michio Kaku pointed out, though the numbers of mankind have multiplied more than a million-fold in two-million years, that does not even begin to describe the situation. Mankind has increased its energies, its structure, its infrastructure, its reaches, complexity, needs and wants, two-million-fold, average per every man, woman and child living, over the same period of time. To even begin to get an idea of what that means, multiply the one-million-fold increase by the two-million-fold increase and arrive at where life, the body of life, is in the womb of Earth today. Your balancing, stabilizing, life, even the individual, into perpetuity in the womb of Earth is an impossibility. And with Space Colonization, we can begin to move people off-planet quickly, ever more quicky, and in growing masses because they will begin to need and want the
migration from Earth to the
manmade model galactic frontier (the growing nova of Alice in Wonderland / Through the Looking Glass rabbit holes into a supernova) in the Solar System far more than sitting still or spinning their wheels on planet Earth.
Don't forget UE, I've mentioned a few times before that I spent the majority of my life engaged directly in a cyber-space-analogue career field to the revolution and evolution I picture. I worked in the early and mid-to-later period universe of that cyber modeling of Solar Systemic networks possible from this mainframe (PLANET Earth) system John von Neumann neverpictured, never predicted, what we have now when he prophesied Utopia-like monolithic systems that would occupy entire city blocks and be so fantastically, infinitely, expensive, though still so closed and limited within themselves, that only the largest, richest, governments and corporations could afford such systems.
Talk about an evolutionary and revolutionary accelerating universe expansion, with a concurrent, coinciding, built-in universe of contraction, we've purposely modeled one with few second thoughts of what we are modeling. And I spent most of my life, career-wise, heavily engaged in the revolutions and evolutions of that modeling (that working model). It was just lucky that I could sit for briefings from Admiral Grace Hopper and others, and that I had a natural affinity for what I was engaged in, and broad and deep secondary interests and studies that matched so well with my careers. Luckier still having a wife and family that not only permitted me it all but gave me space to grow and return much of it to them (though only one really took to it). Enough! for now!
------------------------
"If I had eight hours to cut down a tree, I'd spend seven sharpening my ax." -- Abraham Lincoln.