In many cases a big farming company buys land with a house on it and then lets the house to rot, because they only need the farmland that's around it. And they don't bother to demolish the house, because it costs money.
Going up to family size appartments in recently built middle-class complexes will usually come with pretty good insulation and you won't hear a baby crying at top volume.
And don't get me started on the lack of proper central heating and the use of the stupid portable kerosene heaters. Today I heard from a guy who is working for the village office that the most common emergency call now in winter are from elder people who suffered thermal shock inside their own houses when walking from a warm room to an almost frozen room.
For instance in europe lead pipes were widely used for the internal plumbing and nowadays it’s replaced by rigid and pretty durable polymers. The plumbing goes into the walls, floors, etc. to each place where water goes.
Except that doesn’t work if your walls and floor can shake. You don’t want pipes break into your walls and leak internally. So pipes can’t be rigid, and you’ll have to compromise on durability for flexibility.
When buying an appartment, our plumbing was rated for 30 years. After that, even if everything else is in a perfect state, we’d all have to tear down the building walls and change the plumbing. It can be done, but cost wise it’s not so far from rebuilding from scratch.
Public buildings get away with way longer life by either paying for way more expensive techniques, and/or having the plumbing and any other things that could need inspection or maintenance put outside the walls. It works great, but is ugly as fuck and can have other practical issues (all pipes being exposed has weird safety issues, some europeans house do that and it’s really not great)
And that’s just plumbing.
PS: the second hand housing market is actually super healthy. In particular you get to see how the buildings and neighbors are doing after a few years, and the risk of a bad surprise is that much lower.
PS2: you can live longer than 30y in a house/appartment. Its value just plummets, except if you prove you made all the recommended updates to extend its useful life. It’s basically the same as keeping a car for 40 years. It can be done, but it’s not the generic nor recommended use case.
Here’s one that I found in Takasaki with very little effort.
https://suumo.jp/chukoikkodate/gumma/sc_takasaki/nc_70960514...
Most of the houses being torn down are not what I would consider “perfectly serviceable”. There are usually serious issues such that the home isn’t worth saving.
Small towns really do have programs to give away homes if you commit to remodeling them or tear them down. Even in bigger cities it isn't difficult to find abandoned properties.
(I'll also add: people see things like Cheap Houses Japan, and make incorrect assumptions about the state of the resale market. For a large portion of those "cheap" properties, you'd have to put in 2-3x the sales price just to make them livable. In other words, the owners are trying to solve their financial problem by dumping it on someone else who is more willing to deal with it. This could be appealing for someone who wants a vacation home and loves the area, but it's not a healthy housing market.)
But you’re talking more about markets where there is very little demand (due to declining population) for both new and used housing. Or homes that are in such a state of disrepair that it makes more sense to demolish them and rebuild from scratch.