Home and property owners are effective at organizing against building permits. They have both a desire and a means to stop new building.

The desire to restrict new building permits comes from the understanding that restricting supply shifts the supply curve to the left. They have enough collective bargaining power that they can effectively operate as a block.

Their means comes from Cal. Gov. Code § 65100

> There is in each city and county a planning agency with the powers necessary to carry out the purposes of this title. The legislative body of each city and county shall by ordinance assign the functions of the planning agency to a planning department, one or more planning commissions, administrative bodies or hearing officers, the legislative body itself, or any combination thereof, as it deems appropriate and necessary.

and like you pointed out, the byzantine system of each planning agency. Property owners operate within the system of zoning, at the local level, to stymie new building to restrict supply. Zoning laws allow property owners to effective operate as a cartel.

Still it's important to ask, "How much self-determination are citizens and neighborhoods afforded when it comes to city planning?" or "How can self-determination be balanced against cartelization?"