The two are related. Oil money supports both the suburban Ponzi scheme and also Reaganite deregulation.

My point is, for a city, every square foot of street has an operational cost, and on top of that infrastructure needs to be rebuilt every x years (I think around 20 ~ 25).
While the upfront cost of said infrastructure tends to come from subventions when building a new development, the city needs to cover the costs for both operations and rebuilding once it's needed.

Why does this matter? Well, detached single-family houses provide lower revenue per square foot of street than middle housing or mid-rises, eventually creating a hole in the city's pockets.

I'm not explaining it very well, but I'll suggest taking a look at this:
https://www.strongtowns.org/journal/2023/6/21/whats-the-sweet-spot-for-building-housing-inexpensively
Climate Town - The suburbs are bleeding America Dry

If cities had money, they could build public housing or promote affordable options.

The suburbs are just another part of tax cuts for the rich. They're subsidized by the tax money from more dense parts of the city, which tend to be more poor (and usually filled with ethnicities other than white people - hence the term White Flight).

Singke family homes with big grassy lawns and McDonald's parking lots bring in less tax revenue and cost more money in city services per square foot of land than apartment buildings, being a net drain on the budget. So, there are higher taxes on the poor so that the wealthy suburbanites don't have to see them.

I’m more convinced the human race is gonna die off the way futurama predicted it. The one named “I Dated a Robot”