The other answer IMO is to pick a city no one in tech is even thinking about, and the growth rate is expected to be slow. Not to jynx them but places like Cleveland, Richmond VA, Indianapolis, Philadelphia, Detroit, Columbus, San Antonio, Milwaulkee, etc.
Personally, I far prefer the megacity, but that second list is a potential option.
From an urban development perspective, to me it seems that the best course of action would be a massive federal investment in existing mid-sized cities. Build large public transit networks in some of these becoming desirable cities and distribute the strain tech is putting on our urban centers. Massively increase housing density, but with this foresight, avoid doing the short term luxury development that won't hold up longterm and build some old fashioned 3-5 story brownstones.
The risk is that the people never come, but the alternative is the consistent hollowing out of all major US cities. Something has to give.