Well, I'm not sure how I feel about your first paragraph. I think I see your point, and it's interesting. On the other hand, Europeans have been fighting more or less continuously for a thousand of years, and before the 20th century those wars have never really impaired their ability to be colonists at the same time. So I'm not sure why WWI or WWII would be so different from past European wars.
I'm sure I cannot agree with your second paragraph. I hope I can respectfully disagree without being "disagreeable." The most important resource on this earth is ingenuity, and it's not finite -- it just need liberty so it can flourish. And there's no way we can have any kind of discussion about limiting anyone's reproduction by "force" -- that's never going to happen, nor should it ever happen.
Where the indigenous peoples were primitive and their populations small they were simply overwhelmed and destroyed. Where their numbers were larger they were reduced to serfdom. Where they had strong cultures and huge populations they were conquered and "exploited".
During the long period from 1450 to 1900 it's true that Europeans fought each other but it's not true that "those wars never really impaired their ability to be colonists at the same time". The losers of those wars lost their colonies and their citizens had a more difficult time emigrating.
By 1900 Western technology and ideology had become well-known. The benefits of modern medicine were spreading so that populations were growing everywhere. At the same time weapons were growing far more destructive. World Wars I & II weakened all the European powers, not just the losers. Weakened them very seriously. At the same time anti-colonialist ideologies were spread by the two dominant post-war powers - the United States and the Soviet Union. The British and the French simply did not have the strength to hang on.
The most important resource on this earth is ingenuity, and it's not finite
Of course, its finite. Human beings have never been able to satisfy all their desires...and never will be able to. Unless you believe that war is what humans want most you have to believe that the 20th century was both the most inventive and least inventive century in history - both at the same time.
there's no way we can have any kind of discussion about limiting anyone's reproduction by "force" -- that's never going to happen, nor should it ever happen.
It happens all the time. Just not in an obvious way as is now the case in China.
The four horsemen do their job well and always have. Let the first world close its borders to all immigration from the third world and the birth rate in the latter will plummet radically within 20 years (or the infant mortality rate will climb radically, which is the same thing).