More stringent building regulations probably add to the cost, but the planning system is the big factor. "Desireable area" makes a difference in some cases: a while ago Stoke-on-Trent were selling derelict houses at £1 to anyone who promised to renovate and live in them.
Who will build the infrastructure (roads, electricity, water, sewage)? If you build sth without planning you can block or make it harder to provide these services to others. It only makes sense to plan such thing beforehand.
Planning restrictions are very popular with the local public. So much so that some places in the US invent their own weird private contract law versions (HOAs).
More stringent building regulations probably add to the cost, but the planning system is the big factor. "Desireable area" makes a difference in some cases: a while ago Stoke-on-Trent were selling derelict houses at £1 to anyone who promised to renovate and live in them.