government regulations will be the only thing that can kill it
Regulations concerning exchanges in China are just a first step. I wouldn't be surprised if the Chinese government at some point wants to dismantle Bitcoin even to such a level, that miners will be heavily affected in one way or another. Literally anything can be expected from a government as paranoid as the Chinese.
Besides, it is not only cheap electricity alone, they are also the producers of the mining equipment as such. That basically means that they have another overwhelming edge apart from just electricity, i.e. they get access to the top-notch and cutting-edge hardware and technology before anyone else in the world. Obviously, they exploit this advantage in full
And that cannot be written off either
Hardware is being manufactured in China due to the lower costs, but that doesn't mean every manufacturer of mining gear is in Chinese hands. Does it give them some sort of an advantage? Perhaps, but Chinese influence in Bitcoin is diminishing to eventually such a level, that other than their cost-friendly-climate, there is not much that gives them any sort of significance.