One major factor in the rise in prices is the view of "Property as investment." This is a broad category encompassing "Flippers," investors, and other people not necessarily looking to actually live in the property they've bought. This also includes a humongous contingent of Chinese speculators (
https://www.businessinsider.com/china-investors-inflating-ho... ). The real reason they're investing and speculating, however, is two-fold, and has nothing to do with the real estate market as a thing.
Wealthy Chinese families want to get their money out of China, and thus, overseas real estate is a good way to bank that money outside of the Chinese economy. Couple that with the fact that foreign investors bringing over $500,000 to the United States basically buy citizenship. So, if you're a Chinese family with a factory, and you want your kids to move to the US, go to American colleges, etc. You buy a $650,000 property in Vegas, or SF, or wherever, you send them over, they reap the investment benefits, and get fast tracked to citizenship. Plus, your investment always goes up because the American real estate market always goes up, right?
Well, tariffs and the coming trade war mean those exact types of investors are now pulling out, selling, leaving... That sort of behavior ran us right back to the brink of another bubble bursting, but it slowed a year or two ago and now we're seeing the resulting cooling of real estate markets.
This citizenship loophole was what Jared Kushner's people were giving seminars on in China, presumably to help sell newly made suburban homes over $500,000 to foreign investors. ( https://money.cnn.com/2017/05/06/news/jared-kushner-nicole-f... )