when people think that ethereum will no longer be profitable and give up, chinese miners will be very happy. Mining centralisation will repeat, following the footsteps of bitcoin.
The main problem is many people are not smart, they think "i'll be rich with ETH, it is new gold".
Consider also profit, for European/Us 300/400 $ income monthly are not enought to be a job, on China can be a lot of money of incomming also very cheap elettricity.
Example bitcoins are not minable on West Europe cause elettricity price (0.15 / 0.2 /khw when CH are near 0.05)