I am an architect who, occasionally, has endured the hardship of designing housing developments. Everything is place at the beginning; land that is begging to be put to better use, financing for the construction, etc.
And then all comes to grief on first contact with the local planning authority. The client knows what will sell but the planners want something else. In my area, they want only 1 or 2 bedroom houses. It could be almost any other requirement, badger sets, newt ponds.etc.
And finally, the following documents are generally required on the application.
Planning application forms
Conservation Area Consent Forms
Statement of Community Involvement
Supporting Planning Statement
Design and Access Statement
Affordable Housing Statement
Waste Management Report
Foul Sewage and Utilities Assessment
Section 106 agreements.
All of that is a lot of very expensive paperwork. The local authority then requires the developer the surrender 40% of the houses for 'affordable housing'. The cost of subsidising this is then passed on to the remaining 60% making each of them less affordable and, presumably, increasing the need for affordable housing!
Maybe this explains part of the problem as to why houses don't get built!