I've heard that before and believe it to be true, but then it makes me wonder why cities are often so eager to annex suburban developments? If a suburb isn't paying it's fair share, why don't cities raise taxes or un-annex them? (is there a word for un-annex?)

https://www.strongtowns.org/the-growth-ponzi-scheme/ Cities need to grow new developments to pay for the existing developments.

Presumably when the infrastructure needs to be replaced local governments will finance with bonds (which I think makes a lot of sense). If the bonds are paid for by suburban taxes, do you think the suburbs will get to be as expensive as the city or maybe even more expensive?

The Strong Towns ideology is attractive (especially for northern US cities), but I think if self driving cars come into existence, the ideas might not get very far in most places. Self driving cars are going to encourage sprawl like no other force ever has. I know I'd move further out if I had a self-driving car.

A lot of people don't like to live in cities.

You have to remember a lot of people on this site are young people without families that prioritize social lives. They haven't related yet that people with kids and careers, etc. are simply not interested in what cities have to offer and that the quality of life in a city is terrible if you have a family compared to what you can get outside of a city in a nice town. Unless you're really rich and can get a huge apartment or condo and can afford to pay for parking or have a driver, etc.

Just look at NYC to find the typical pattern: Young person lives with multiple people in an area like the Lower East Side or Williamsburg (yay social life!), then begins to settle down in a place like Park Slope (just married!) and has a kid (dedicated to urban living) and then another kid comes along and/or the reality of urban living (the schools are awful, it's cramped and expensive, the city offers you nearly nothing since you don't go out like you used to) and the brownstone is sold for a tidy profit and they're off to the NYC suburbs to get more space and a better quality of life to raise a family in. The city is a short commute away still.

That’s a separate issue from suburbs’ environmental impact. I’m all for raising property taxes in suburbs to make their residents pay their fair share for infrastructure.