I doubt that it will collapse, it may have significant effect on the ecosystem. But to say that it will fall just because of China banning bitcoin mining is absurd. And I'm sure big mining companies inside China has already a plan B in case the government made that bold move. At least if this happens, then it can break the monopoly and I'm sure there will be companies and countries will to take the lead.
I agree with you as i believe that Mining companies in China have already exit plan to continue their operation in case of Banning and besides not only China has affordable electricity in the world because their are lot of places that can match their cost that even much little expensive but still it is better than their enterprise will not continue operating.