Look at Manhattan or Hong Kong. You just stack the homes and offices and stores on top of each other.
https://blog.epa.gov/2015/07/14/the-manhattan-skyline-why-ar... https://en.wikipedia.org/wiki/Geology_of_Hong_Kong
Chicago typically doesn't have well accessible bedrock. I know of one civil engineer who unexpectedly ran into granite and was able to sell it for added profit on a project. Point being, CE's don't typically expect great bedrock yet have developed methods to build skyscrapers in a city that was formerly a swamp.
"He says even though new technology makes it easier to find solid bedrock beneath 100 feet of wet clay, it doesn’t always make sense to drill that deep. Modern engineers still use the same general principle Burnham & Root employed when they floated the foundations of the Monadnock Building on an even flimsier layer of soil known as desiccated crust: They just spread the load."[1]
[1] https://www.wbez.org/stories/building-skyscrapers-on-chicago...
And the choice it's entirely driven by financial speculation, nothing else.
And the problem they search for has been solved half a century ago — the modern highrise apartment building.
Then on the 6th floor have a pedestrian/cycle floor that's sheltered from the elements, and the 7th floor have open parks, with 30 stories of housing and offices above.
People who fall for stuff like Hyperloop. The biggest problem with housing is not the building itself, its the land and the scarcity of it. This is yet another tech 'solution' in search of a problem. And that problem is political, not technical.
INB4: but we're gonna deploy these on Mars!!