That's because you're using planned economy principles for your cities.

Remove all zoning but for industrial zoning, and remove prop 13, like it is in most of Europe, and the invisible hand of the market will transform most of cities into medium-density mixed-use like in Europe, though in your case likely accomplished with 5-over-1s instead.

And with increased density, maybe you'd even have space for some public parks again.

Not big, sprawled - because of cars. In terms of population, most US cities are not very impressive.