They glossed over one of the biggest reasons houses are demolished after a few decades: earthquakes. Thirty years of earthquakes will ruin any house that's not a bomb shelter.
No, the real reason is the delta between a tiny but valuable home and junk in 30 years is not that high because construction is cheap due to climate and the time value of money eat's what little value might be there. For most people they get most of there value from simply living in the house.
PS: US, also spends a lot of our GDP on housing construction we just value the land vs home differently because of cultural reasons and construction materials. Despite the demonstration from the rust belt that it's mostly the land that's valuable not cheap homes. aka location location location
I live in San Francisco, and I can tell you that old houses here suck. Many door frames have shifted, so doors have trouble closing. Often, the door has been replaced with a smaller one, leaving giant air gaps. Ditto for windows. They don't seal well, or they jam easily. Floors aren't level. Pillars are noticeably crooked. It's crazy, but San Francisco makes it really hard to build new stuff.
Also, the bay area isn't nearly as geologically active as the Kanto region. If San Francisco had earthquakes of the frequency and scale of Tokyo, hardly any low-rise in the city would last more than 30 years.
That's funny - San Francisco, legend has it, has a lot of New Zealand Kauri in the houses, built from ships returning otherwise empty after helping fuel the gold rush in New Zealand. Similarly, our houses down here are cold and filled with draughts. But before you get all hasty, don't seal those gaps up. I tried this. Without the ventilation you will get mould. So cold it remains. Pulling all the seals off made me sad, but it was a quick fix. For the record, I'd choose and older house over a new one in a heart beat. Dents and scratches just add character to an old home. In a new house the wood often seems to be laminate, the benches Formica or composite etc. Systems, if you can call them that, are damn simple on old houses. This is good, as you will spend a lot of time crawling around them, fixing, replacing borer bombing and generally making lost ground.
It gets colder in Tokyo, too. Those "air gaps" and poorly sealing windows make for chilly winters indoors. And I'm sure houses these days are built with better insulation than they were twenty or thirty years ago, too.
Not to sound like a 50's handyman. (http://www.familyhandyman.com/doors/repair/fix-sagging-or-st...) However, replacing / rehanging doors and windows and doors is generally a fast and easy thing to do and more or less required as wood flows and settles in an older home. Really what your talking about has more to do with a generally mild climate enabling a lack of maintenance vs. any kind of earthquake damage.
PS: I stayed at a a 100 year old farm house made by complete Amateurs and built on over time where some of the floors and trim sloped more than 5 degrees which is vary noticeable to the naked eye. Yet it had decent insulation, every door opened freely and most windows opened just fine. It took a few people a few weekends to get it there, but vary little cash. A respectable carpenter can do the same thing for you for about 10k every 15-20 years. Again though the difference without cold winters there is far less incentive to actually deal with such things.
Edit: The science behind it is even fairly interesting, but basically wood reacts to the forces on it over time so the less symmetric the home the more extreme the warping can get. Which again hurts Japan with there love of unusual shaped wooden homes.
That's not really a reason. Romania has an active epicenter of earthquakes and the houses are not demolished/rebuilt that often. When designing and constructing buildings, there are also just some seismic requirements, that's all. There isn't any planned obsolescence involved and I haven't heard of much earthquake damage since 1977.
