I would say that most miners won't leave their country unless mining is the biggest source of income that they have, and the only one sustaining them. It is *possible* that miners will move their operations out of China, but I don't think most will if they have another form of employment. They may move the equipment out of the country and have it managed by international members, but it's a lot harder to move citizenship between countries than you'd think. Doing all of that just to keep mining Bitcoin is dicey.
All of your other points are correct, however. Hobby miners won't get anywhere (still) and most industrial miners will continue to get bigger.
Miners do not really have to leave their country, they only need to transfer out their operations. These are rather different things. Considering also that most big China based miners actually had very close relationships with power providers,,, I remember a lot of them had individual deals with hydro companies,,, I think more is made out of the issue than really is.