Japan has reasonable real estate and yet around 10% is in Tokyo proper, nearly 30% in the greater metropolis. Less than half own their homes.
This study: https://www.sciencedirect.com/science/article/pii/S026427512... from 2023 shows that they're suffering similar issues of intergenerational wealth transfer when it comes to owning homes, specifically if your parents don't help you - you're unlikely to be able to get on the ladder.
There are a ton of homes that are not claimed but purchasing them, their value, the land value are all - as you know - quite different from the US/AUS/India where the value goes up. Different from the UK where you own the home, but lease the land etc.
In general it's only flats (apartments) that are leasehold, the majority of houses are freehold.
>There are a ton of homes that are not claimed
Those are in rural places with dwindling populations, where no one wants to live any more.
It's just that we don't do it because of housing shortages, or the ever popular terraced housing, and people live in some of the worst states.
Looking at the listings in a broad radius around me, there is still a lot of housing built in the 1960s and 1970s being bought and sold quite regularly, and some stuff even older. A house built in 2004 ("a couple decades") would absolutely not be worth the cost to rebuild.
There is some real estate inflation in very desirable parts of the biggest cities because of foreign investment, but I'd say it's limited. There's still lots of new construction going on, though it's slowing due to labor shortages. The foreign investment can only go so far: real estate isn't a great investment here because structures depreciate rapidly, and it's relatively easy to build new housing just about anywhere if you own the land.
So it does not help the housing problem all that much - sure there are now houses available in the countryside but no one wants to move there.