Look carefully, the house on the pictures I posted isn't made of wood.
Though there are still many wooden houses that are 120 years old, that haven't been demolished by earthquakes during that︀ all that time and are still looking fine.
But I know where you come from,︁ houses in JP "aren't supposed to last longer than 40 years" as you mentioned, but︂ the real reason is that otherwise one big part of Japanese economy would suffer. They︃ need someone to sell their shitty overpriced mass produced new houses to, and demolishing and︄ rebuilding every 40 years keeps their children employed.
That earthquake issue is overblown anyway, I︅ lived in a few old houses in Kanto, and all that earthquakes just made the︆ glasses shake, but no damages to the houses. And you can bet some of them︇ were >40 years old and are not up to date to any of that new︈ building codes. The real issue not if your house survives, if the big earthquake comes︉ and Mt.Fuji errupts, even people in Tokyo gonna have huge issues, as logistics would disrupt︊ the food supply and the supermarkets would run out of food in a day (remember︋ toilet paper and masks?). Hungry people are easy to manipulate, and bad things happen quickly,︌ see the last great Kanto earthquake, where Japanese police murdered 6000 Korean and Chinese, after︍ spreading rumors about Koreans poisoning wells.
Kantō Massacre - Wikipedia
Anyway, back to subject: I︎ haven't been talking about new housing. Though it takes a bit of diligence, time to️ find good deals and paying someone to check the structures, some akiya's are a great bargain, and offer an easy life in a developed Asian country, with first class women as well. Cost wise, food at the supermarket is even cheaper than Thailand now.
