A lot of cities constructed their suburbs with one-term fees and subsidies, but are charging extremely low taxes on the houses once constructed. In fact, the taxes are so low that they don't pay for the upkeep of the infrastructure required to service those houses. They are losing money on every house and are trying to make up for it in volume! The sole reason they have been able to continue is because the dense urban core is subsidizing the suburbs.

But it'll inevitably end up with decrepit and neglected infrastructure, and cities going bankrupt. The only way to solve this is to increase the revenue per land area, which means a higher land tax, which in turn means a bigger tax increase per-person for single-family homes than for multi-family dwellings.

If you want to know more, the following NotJustBikes videos are a good introduction of the subject: https://www.youtube.com/watch?v=7IsMeKl-Sv0 https://www.youtube.com/watch?v=XfQUOHlAocY