> The real reason, quite bluntly, is overpopulation. Our natural population density is what the land can support from hunting and gathering;
That would be 10 million humans globally.
The invention of agriculture, and the gradual improvements until the 1750s (The Wealth of Nations essentially invented/formalised the foundation ideas now called capitalism in 1776), took us up to a 791 million.
Capitalism (mixed with ongoing feudalism) took us up to about 1.2-1.7 billion, then a mixture of capitalism and communism took us to about 5.4 billion.
The examples you're giving of food shortages are mostly in the past (certainly in developed nations with the highest house prices), specifically because of the heavy industrialisation that allows us to over-produce almost all years, which is why we've got large scale issues with obesity rather than hunger.
> The end result is the anthill cities that we consider the norm today.
No, "anthill" is a choice. Look outside your own city, and you see large swathes of countryside, with hardly anyone in it. Or look at a different city — I've visited the Bay Area, and that's mostly houses, with a few zones of towers; I've visited Manhattan, and that's concrete canyons; I've visited Athens, and that's a mix of densely-packed narrow lanes and broad avenues, surrounded by low-rise apartments; I live in Berlin, whose inner city is almost entirely low-rise, and whose outer zones are a mixture of detached houses, farms(!), and woodland; I used to live in Cambridge (the original one), where cows are frequently found grazing in the inner-city fields (and yet people still complain about it being 'over-crowded' rather than making a pun like 'over cow-ded'); I grew up in the South Hampshire conurbation[0], which is "the most populated part of South East England excluding London" and… well: https://www.google.com/maps/@50.8550817,-1.0769807,3a,75y,10...
> Our monkey brain is still not adapted to such an environment, though, and wants to reduce the density to what it expects; hence NIMBYism, anti-immigration, zoning, race covenants etc - which all boil down to the same basic idea that if we drive out "them", then "us" will have all the (obviously abundant) resources of this land for ourselves. Of course, that's not how our modern economy actually works, but the monkey brain does not operate on a rational level.
That, I agree with. Though I am also saying you (and, to be fair, I) also have monkey brains thinking monkey thoughts — we didn't evolve to know a world beyond what we could easily reach on our legs, and for many of us the countryside a few tens miles away may as well be on the moon.
[0] https://en.wikipedia.org/wiki/South_Hampshire