That's tautologically true of course. What is far less clear cut is whether it's preferable for someone (and their children) to stay in a country with a bad regime that's improving or in one with a good regime that's deteriorating. It depends on many factors (levels of goodness/badness, rate of improvement/deterioration, persistence and stability of trends, how one is personally affected by goodness/badness/improvements/deterioration).

To make it more concrete, there are people (granted, overwhelmingly ethnically Had Chinese fluent in the language) who voluntarily choose to reside in China over the US or EU, and I don't think they are irrational about it.