I gather that there are a number of factors.
In part, there is a kind of "build it and they will come" approach. Mianzi(face) is important to the Chinese in ways that don't translate well to our way of thinking sometimes. Have a house, even a pretty crappy one, and you're able to claim you are someone in comparison to those who don't. Have a house and (in a country with 40 million too many men) you have a shot a getting married, good luck without one -- thanks to gender imbalance bride prices have come back with a vengeance. China also uses an internal registration system for citizens (hukou) and having a house is one way to try to nail down a better location for your registration. [It is complicated, with various local twists, but think of it slightly like Americans who want to live in a good school district taken to a much more extreme level.]
In part it is a kind of WPA (Works Progress Administration) effort to keep migrant workers employed, while also shoring up economic growth figures. @Rasulis gave an accurate account of how some of that plays out, all I'd add is that in some cases the construction is seen as stop gap. There is an expectation that if an area is successful, existing buildings will be torn down and replaced with increasingly shiny, new complexes. That is seen as one way the construction industry can be kept rolling, while at the same time those who bought in early are able to cash out at an often considerable profit. It looks like a kind of win-win situation, but in reality may come closer to being akin to a Ponzi scheme in some situations.
Side note: It may seem odd to think of apartment complexes as almost temporary structures, but property ownership in China is closer to a life estate (again, it is complicated). For what it it worth, I remember being sent to Europe to pitch a popular American building material. It went over like a lead balloon, with the Germans in particular giving me an earful about how they viewed American construction as inferior for using framing and drywall. As one guy put it: "we build things to last 100 years and more".
The other problem, of course, is corruption. Everyone in the process is apt to be doing something to skim some of the money off, to put money in a bank and take advantage of interest and special offers, to trade favors or in some other baroque manner get something out of the deal. As you might imagine, this means that there are a whole bunch of people who want something built, and how it finally plays out isn't really their major interest. Once again, mianzi plays into this because it fuels the desire to have bigger, newer, longer, higher, or shinier projects.
Those of you who aren't behind the Great Firewall will find plenty of articles discussing these things, but these points may help you get started.
One day at a time, often with fits of coughing when the air gets bad, and then something akin to the cough smokers get when they quit smoking if the air clears up significantly. Masks for PM2.5, air filters, and various medicines may also be involved.Originally Posted by Strawberry
Let me recommend a book to you: The Geography of Thought. Dating across different cultures can run into odd disconnects and it helps to have an idea where some of the differences might come from.