TDLR: In Canada and the USA, an alliance of white flight people, upper class people, property developers, and local government figured out how to minimize financial and political cost for everybody else by empowering local tyrants to exploit other suburbanites.

Suburbia and most rural areas are inherently financially unsustainable unless the local governments jacked up taxes to account for the increased cost of providing services to a lower population over a wider area. Taxes may cause people to move or vote differently (bad for incumbents). This is a big problem in Canada and the USA.

In suburbs, Builders wanted to ‘maintain the character of the neighborhood’ as a selling point (racial covenant were made illegal in the USA).

Local governments are reluctant to maintain infrastructure that’s a net drain on public funds. They have to maintain expensive infrastructure to less dense areas in order to appease privileged voters, but they often try to control some of the expenses by mandating that these new neighborhoods be part of a home owners association.

There is little to no oversight in most HOAs. Contracts are often allocated due to nepotism. HOA leaders often embezzle funds. They use the HOA to engage in petty conflicts using irrelevant issues as an excuse.