Where in the country do we really have an honest overcrowding issue?
The affordability of cities is far more about the wage disparity between workers, not over crowding.
And most sprawl happens where there is nothing, so there's no character to ruin. Unless you have firm examples of small towns being taken down so that strip malls can be put in. Around here, the smaller towns that are in Metro Detroit are getting some injections due to people moving to the area, and buying homes on the fringes on those towns.
If you are talking about the cultural character, then you totally have forgotten that each of those towns has their character built 100% by immigrants. Small German or English or Italian or Polish or Swedish or Finnish towns were all established via immigrants. And none of them stretch back much more than 100 years- hardly old history. So now they have shifted from native American to French/British/Spanish (depending on where in the country) to some other country and now again to another group. Hardly new nor a big deal.
Lastly- before complaining about the overcrowding of 42m new people, how about look into where they go. Which is largely rural farm areas, which have been consistently dropping in population, as the people who are FROM there move away.