You don't understand
they cut ties with one or another western company - they lose money
but if they would stay with this foreign company as ambassadors then after a week or two Idols would be banned by Chinese state regulators, and they wouldn't be ever able to perform, as well as sell songs/albums. They would be treated as criminals. And yeah their families will be pressed...
not to mention that if they would try to flee to another country Chinese government would either stop them and jail them or at least block their bank accounts. Which means all those years of hard work would end as them being broken.
Yes this is actually true, do some of the idols do it because they are brainwashed 10cent army? Yes but the vast majority aren't. If people would get their heads out of their own asses go live overseas for awhile, you will see just how dangerous the CCP is. What you just described in your post is 100% true that does happen should you not tow the party line.