ok listen... I hate it.... but I also kinda love it. I want the future. I want the sci-fi utopia.... I want to have better urban planning. but also.... we're not really that good at living on top of each other.
I love arcologies. I own a first edition of this. I have maybe five books on earth-sheltered habitat, which always come down to some form of arcology because you're much better off building the whole damn thing underground. Unfortunately, arcologies generally fly in the face of "the city is there because it's a natural place for a city to be" in favor of "the city is there because it stands as a testament to our own hubris." Historically, humans live on top of each other without a whole lot of difficulty. The Sumerians and Babylonians were basically communist and their collectively occupied cities lasted three or four thousand years. Feudalists and market capitalists suck at living on top of each other.