Land is definitely not cheap in places people actually want to live, and land is the thing that is appreciating over time, not the structure.

The building does appreciate sometimes, at least here in Germany because the increasing absurdity of bureaucracy and regulations make the same class of house more and more expensive to build. At the same time, "lower classes" of houses become outright illegal to erect, leaving only the luxury segment for new buildings. Old buildings have grandfather privilege and thus become more expensive than an equivalent new build would be, simply because you aren't allowed to build new.

Right, I'd figured there are exceptions to my assessment, and my view is only from the US. Many homes in the US are are seemingly being built with lower quality/faster timelines, and I personally would not want to see what they look like in 30 years...

There is also the consideration that "lifestyle" appreciation can also happen. If an area gets really built up, more things are happening in the neighborhood that make it a more appealing place to live in, the allure of that lifestyle will push people to buy homes that are probably not worth much in another location.

My (UK) house is worth 3x the total rebuild value my mortgage provider wanted me to insure it for. This implies the land it’s built on (and the planning permission to build the house) is worth twice what the structure is worth.

Unfortunately things like prefab buildings that could cut costs in half do tend to be illegal

This is not even close to true.

Land can be very expensive. Especially when it has infrastructure built out to it already.

Land is not cheap in the UK.

And unless your property is Freehold, you don't own the land at all.

To be fair, most properties in the UK are freehold.

Not in Scotland

_Especially_ in Scotland, since Scotland doesn't have leasehold the way England and Wales do.

In King County WA the assessment would have two line items.

    Land: 500,000
    Improvement: 300,000

They tax that at $800,000

I seen plenty of land around that area for $150k or less. No doubt some land is worth $500k plenty is not anywhere near that.

In desired areas land is about 80% of the house price, that's why if you add zoning you obly get exyremely expansive single family houses where you could get cheat multi family high rises