I'm not sure if the ghost stuff is really indicative of a failing economy. I mean, China is about 20% of the world population, you're bound to find emptiness. We're talking about city planning on a massive scale. 220 cities of >1m people are expected by 2025. (SF at 0.8m by comparison). China has multiple cities bigger than countries like the Netherlands, multiple cities 4x bigger than Norway that was recently in the news. It has 280m (rural) internal migrants. Compare it to the US working age population of is just 200m.
The numbers are insane. In the US, we move 11x in our lifetimes of ~80y aka 13% of our population moves each year. Apply that average to China and you're looking at 170m migrants annually. And unlike US (a lot of urban to urban), in China there's a gigantic one-way rural->urban traffic, i.e., two people aren't switching urban houses and calling it 'moving', two people are leaving behind a rural home and needing an entirely newly built urban home.
How do you accommodate that many people in new homes. Do you start building homes only after they're needed? Or do you build some capacity at a surplus, to cover expected growth?
Probably the latter. It isn't much different from any company stocking surplus inventory. That's not an immediate indication of a failure of economics and a bubble.
And do you only build in existing popular cities and just try to add to the periphery, or do you build-up new cities? Probably the latter, too.
Plenty of other countries do it as well. Incheon developed very much due to overdevelopment in Seoul. Or here in the Netherlands, we now have close 0.8m people living in so called Vinexwijken. They're a development centered on a new ordinance concerning housing development between 1995 and 2005. Since 1995 our population grew by 1.6m or so, apparently half our growth went to these new locations created out of nothing. And we always have discussions about structural emptiness, big malls being built and remaining 75% empty for years. But the scale is smaller, the country is 75x smaller than China. We had issues with structural vacancy rates at a new 100k 'village', scale that up to 75x and you have a similar story. Yet the biggest ghosttown in China ia Ordos, planned for 1 million people, scaled back and built for 'only' 300k, and currently houses more than 100k and climbing. That's what is consistently called the biggest ghost town in China. For Chinese, both the size of the project as well as the timeframe (10 years of vacancy) is a rounding error.
Don't get me wrong, there's definitely an asset bubble. But we've also been saying that for who knows how many years and I feel we tend to focus too much on symbolism of the ghost town narrative.