https://www.strongtowns.org/journal/2011/6/16/the-growth-pon...

From part 4: talking about the 70s when infrastructure maintanence and replacement bills started coming due "The critical insight today is to understand how we reacted to the end of the first life cycle of suburban development, when those maintenance costs started to come due and cut into our growth-generated wealth. This time there was no spatial shift as seen in the other large, economic corrections. Instead, we made a choice to double down on the suburban experiment by taking on debt.

We used debt to drive additional growth and sustain the unsustainable development pattern for a while longer. A lot of this debt was public debt, but we facilitated mechanisms for increases in private debt as well (for example, Fannie and Freddie early on and then subprime mortgages and securitization later). Here is a graph showing our public and private debt levels since the beginning of the suburban experiment. I have noted roughly the first and second life cycles of those initial investments."