They are built on land that is relatively scarce (in suburban areas, and the UK scarce full stop), zoned by local government, subject to the influence of regulations and unions etc.
House builders in the UK quite clearly hold back on (or try to corrupt their way out of) large developments that require them to build social housing, they seem to have slowed down building in response to threatened law changes around leaseholds (which are onerous and abusive), and they appear to hold back on smaller projects as leverage with local governments in discussions about the regulations that are stopping them taking on larger projects.
They are absolutely willing to build fewer houses than they could, and they tend to be rewarded for this with higher prices, because the barriers to entry in building houses at scale are really significant.
They are built on land that is relatively scarce (in suburban areas, and the UK scarce full stop), zoned by local government, subject to the influence of regulations and unions etc.
House builders in the UK quite clearly hold back on (or try to corrupt their way out of) large developments that require them to build social housing, they seem to have slowed down building in response to threatened law changes around leaseholds (which are onerous and abusive), and they appear to hold back on smaller projects as leverage with local governments in discussions about the regulations that are stopping them taking on larger projects.
They are absolutely willing to build fewer houses than they could, and they tend to be rewarded for this with higher prices, because the barriers to entry in building houses at scale are really significant.