> Vacant land that's desirable is often held back from development due to zoning or infrastructure issues.
Nah, it's mostly speculation. Zoning/infrastructure issues get baked into the price. If you cannot build anything on a plot of land, its price falls.
Until someone gets the zoning board to wave a magic wand and change the allowable uses of the property, and then it's a lot more valuable.
This happens all the time, and is a major reason why people will sit on land for extended periods of time.
Only at point of buying. If you buy some land and the mayor suddenly implements rent control then the value goes down.