It's a strange thing, that they didn't try to diversify their buisness before. The were not much law regulation of crypto related activity all around the globe. Without them it's always risky to base a company in one country.
Moving out would mean hiring additional staff elsewhere. Those mining operations aren't manned by a lot of people. Sometimes it's just 2 guys running maintenance for a huge farm the size of a football field. They live and work there having beds and everything set up on site. Also there's the matter of security. You know your local area, moving to another country and setting up there is always more risky.
This has to be expected, those greedy Chinese should have smell it from afar that the government is really clamping everything that has bitcoin sign all over it. One thing that I'm seeing is that if they are really banning it, the price will be severely affected, just like when they banned ICO and closes their local trading platform.
I think they're making a critical mistake by pulling this off, they already pulled of something similar back in september and that only caused a temporary price decrease. If China wants to get rid of all the bitcoin miners and mining companies in China they will move elsewhere it's that simple.
That's the beauty of capitalism and internet-based companies. You can run them from anywhere in the world and banning something in one country only means that another one will earn more. When the miners leave China will have an abundance of power that nobody will be using and much less money from taxes. The problem with power plants is that they're the most efficient when they're going at 100%. They will be producing all this power that used to be drawn by the miners anyway but nobody will pay for it. It will just go to waste. The Chinese gov is so stupid.