> I think that, in the UK, you don’t actually own the land your house sits on; Lord Such-and-Such owns it, and collects rent from you.

This isn't quite right.

There's something kinda like that called leasehold, where you basically own an extremely long lease on a property (typically 70+ years, often up to 999 years), with the freehold (outright ownership) sitting beneath it. Generally it's used on apartment blocks and certain new-builds in specific areas (e.g. they're more common in London, but outright banned in Scotland outside of some pre-existing edge cases). There's a good chance the whole thing will be functionally reformed out of existence in the near future (see here https://commonslibrary.parliament.uk/leasehold-reform-in-eng...).

But in any case, the vast majority of UK property is sold freehold, or as you put it "we own the land, and that is usually the real value".