That means Labor is less than 25% of the cost. And labor isn't really THAT much cheaper in China than, say, Poland anymore.
Further, China has 1.6B people and 33% of it is mountains -- 69% highlands. It's not insane that land is more expensive than in, say, Serbia.
Finally, the world has never seen almost 600M people migrate to cities in 28 years time. Demand is unmatched in history.
That being said, China's average income per person is about 1/4th what it is in Germany, yet the average house costs nearly double -- with higher interest rates. AND, you only get a 99 year lease on the land you buy there, you can't own it. Taxes are different, sure, but it does seem like prices are quite high.
Sure, regulations might be more lax in China. But, the point is, the Chinese market is very different from Western markets.
The main thing expensive about housing in China is the land. The labor is cheap (but inefficient), the concrete is cheap (if overused).
There are entire “ghost cities” of empty housing only a few years after being built, completely dilapidated.
I think most residential construction in China has a shelf life of around 30 years before they have to tear it down and do it again. This is because they favor labor intensive but skills light concrete techniques that require a bit of overbuilding. That way, they can keep uneducated migrant workers employed.
There are places in drug lord countries like Central and South America where e.g. condominium prices are $300,000 USD minimum, while people living there are lucky to earn $20-30 USD per day.
In London the average flat price is like $700,000 and a lot of people make $60-70 us per day here...
another factor, a lot people believe the housing price will not go down. so, people buy house to make money.