Comment by prawn

Zoning changes would generally make your property more value as a baseline. Then you could either stay put, or you could elect to move elsewhere while redeveloping your original place. This is common in Australia.

A common zoning change here is based on street frontage for semi-detached homes - the new ones are still 3-4BR, just attached at the garage and with smaller yards. If development required 15m frontage, but then that changed to 12-13m, that would mobilise a lot of owners to take advantage, though obviously others can just stay as is if they prefer.

It usually happens that an $800k lot value becomes $1m, regardless of the state of the house. The owner can then demolish a decades old house, build two places for $600k, sell one as a new home for $800k-1m to finance the build (and costs of moving out during that phase), and end up in a new house themselves. Often they've sacrificed yard that they found annoying to maintain anyway.

The above can be adjusted where it's possible to build 3-4 on a block, or a larger development of apartments.

Zone changes typically allow change, not force it, surely? An owner can just keep their SFH and large yard if they prefer. What they can't always control and often vote against is the composition of their neighbourhood.