The question that must be asked, why with the stagnant population, cities need to keep expanding? Maybe it's unwise to move young, rich and actively working people to city centers with no shelters and no chance to escape? Maybe this is what left wants America to do because they are CCP sock puppets and want to make America more vulnerable? Suburbs are at least safe: too widely spread out to be targeted, have plots big enough to have insufficient density of combustible material to produce firestorms, and mostly have basements to be used as shelters.
Maybe wise policy will be to make it unattractive to move to big cities (say, by truly crippling taxes), to force people to spread out? If they don't flock to a limited number of megacities, there's more than enough space for everyone to live in a suburb.