Makes sense I wasn't thinking about the full on laundering aspects. But even so, if the real estate is used in laundering, it will eventually have to be sold to get back clean money. This should still run up prices at the start, and run them down in the end. So I think the majority of the point still stands: there should be an uptick in sales (which there is not). They could be speculating on top of laundering, in which case they are taking some losses. We are -20% from peak. The time will come when they (the launderers) will need liquidity and sell which has not come. Will it ever come?
They can get clean money from the start if they structure things right.
Have other mules or partners purchase crappy properties at a low price. "Flip" the properties, having another mule purchase at a greatly increased price and service the mortgage with more laundered money.
So you get the capital gains immediately, and they are apparently completely clean. If the crappy house continues to appreciate naturally, that's also a bonus, but if not, you can eventually default the mortgage or short-sale.
I think they want to get their money out of china and parked into a safe place. If they pay off their mortgage, they don't want to find a new place to park their money, they can just keep the house as an asset. I think a lot of investing in china is real estate based and is part of the reason that market is struggling over there so much now. It would make sense for them to continue to follow that investing model when exporting their wealth to other countries.