Despite the uniformed nonsense you might read here, the most active NIMBYs aren't primarily motivated by property values. If you actually talk to them you'll find that they have no wish to ever sell and are worried (sometimes irrationally) about quality of life issues: noise, parking, traffic, crime, privacy, etc.
You misunderstand. Most of them aren't specifically concerned with neighborhood character. They are mostly long-term resident homeowners (not landlords) who don't want the hassle and annoyance that comes with higher density. If you want to counteract their efforts then at least understand their motivations instead of treating them like caracitures.
At some point someone with authority just has to draw the line. Those people’s desires to not be hassled is not important, and the need for sufficient housing supply is.
Imagine you spend half your working class life saving for an absolute shit hole for half a million, knowing it's an NFT that no one can build more of. Then permitting laws are liberalized and suddenly your NFT is worth no more than the labor and material cost to physically build the house, minus depreciation.
It's difficult because losing that NFT means they are fucked in retirement. Oh well for them, stupid them for wanting a house while nimby zoning was in effect.
The losers unfortunately won't be the boomers that made the dumbass laws but the people they squeezed afterwards. It's a totally fucked situation.
The value is in the land, not the house. If you own a plot of land with a single family house on it, and suddenly someone is able to build an apartment building on that piece of land, it will actually become much more valuable because an apartment building generates much more revenue than a SFH. They could easily sell the land to a developer and retire somewhere else.
It's not obvious that would stay fixed: depending on the dynamics of the market, it could go up, it cold go down (The demand is for housing, not land. If you manage to increase supply for housing sufficiently by increasing density, then the value is the land could go down even if you could build many more homes on it than before). I agree it's not certain that it would go down, however.
It becomes obvious as housing density approaches infinity. Why would anyone buy your land for housing if they need one tiny spec to house a billion? This is simple supply and demand, high density housing lowers land value, as price isn't determined primarily by potential utility .
Sure, you can always make an obvious argument at an extreme, but then you need to demonstrate that the extreme is relevant (like, the function is monotonic, not very common in economics).
Why on earth would apartment builder buy my land specifically for housing when they can dump a mega apartment complex anywhere? This is simple supply and demand.
As density limits rise, housing land demand lowers. In the extreme of infinite density, demand goes to zero, as everyone can fit in a pinpoint and we don't need other land for housing. We get the opposite as your prediction as everyone lowers prices hoping to undercut to get the single pinpoint bid.
I hope it's clear that I'm not blaming the average person caught up in the housing market for the broader climate in which they live. It is fucked and I don't see a way out. If we build enough housing the price of their retirement asset drops and they are fucked and if we don't then we continue seeing mass homelessness and dropping birth rates.
I don't have a solution, I'm commenting that the typical things that are blamed for the housing shortage are symptoms not causes.
