China’s doing it too. They bought ARM shortly after Brexit.
I don’t doubt that there is a migratory factor, though I don’t believe it’s primarily due to salary or other compensation as I assume you’re inferring- a cornucopia of tech giants is going to attract talent from the world over.
So a consequence of centralisation is more centralisation.
I thought SoftBank is Japanese, not Chinese? SoftBank bought ARM, not a Chinese company, otherwise it would be a bit weird for ARM (assuming they're Chinese now) to cut ties with Huewai.