I don't think China will be able to take over the bitcoin network, because we know the Chinese government really hates bitcoin, but I admit that China dominates in bitcoin mining, but if the problem is they want to take over the bitcoin network, I don't think it will be possible, even though they do. any way, I'm sure they will not be able to do it all..
The hatred for bitcoin is all the much more reason to takeover the network of bitcoin, they could've done that but luckily they thought that dominating the network is futile effort since the market can recover but and they will probably spend a lot of resources just to do that. Also they can't dominate anymore if most mines in their country are gone.