Housing and land prices are a function of supply and demand.
Every time a city rezones a single family area they reduce the supply of houses by that amount.
Most of these owners repurchase at least one new home with less available. Plus a significantly increasing population.
Every time the city rezones these single family areas more redevelopable land is created.
As demand increases from growing population the supply also increase from new areas getting rezoned.
The bigger the gain the better off you are from selling. The gain is the extra money made from selling as a land assembly vs. selling as a house. Here is how to calculate the gain:
If your land price goes up less over time then your replacement cost (the gain from selling as a land assembly) will decrease.
In the future, houses available and land available = replacement house costs and gain from house value to land value.