This is kind of ignoring all the positive effects from density. Yes, housing for density is hard. Yes, there are some negatives. But you would not get anywhere near the economic productivity you do from 330 Million people uniformly spread across the US as you do from having huge spikes in NYC and LA (and other metropolitan zones).

You also have to face the fact that as you spread people out, most costs go up. Cities subsidize suburbia and rural areas in the sense that cities generate more tax revenues of all types relative to costs. Suburban and rural areas mostly fail to raise enough tax revenue to pay for their own infrastructure and generally rely on various handouts from state and federal governments to build things like sewers and roads, which they then do not adequately maintain due to budget shortfalls.