[dizzariot]

...it is legitimately like Corbic says. The bigger metropolitan areas are also subject to the corrugated steel/poorly formed concrete buildings but the cameras don't get pointed there. Tokyo, Yokohama, Fukuoka, etc all have these old buildings.

There is a situation in Japan where the older neighborhoods/cities are almost ghost towns. parents grew up in these cities with a sense of community but their offspring typically want to head out for a life in the city when the time comes. The parents get old, house gets too hard to take care of, and then when the parents pass the kids do not care to reclaim the home and fix it up. So they just sit. I went on a roadtrip to/through Takayama and at nightfall there were absolutely no lights on in any houses, the konbinis were all boarded up, and it looked like people just...stopped living there.

Also, steel is NOT a good choice for the climate lol. That's why all the steel on these old buildings is rotting away. The humidity here is bonkers during the summer months. I think mav is talking about steel-reinforced concrete buildings and corbic is talking about the roofs and outer panels of some of these 'less-than-nice- houses.

TL;DR - Like everything else in life, Japan is not some glorious mecca that the influencer pages show you. There is a lot of 'ugly', a bunch of terrible roads, and abandoned buildings. You could compare this effect to seeing romanticized pictures of Europe and then actually visiting.