Money is just a social contract though. What they can’t take with them are the means of production. Stuff like factories that they used to own will stay in China. What people in the west don’t seem to understand is that the economy is fundamentally about allocation of labor and resources towards meeting the needs of the people. Money of itself has no inherent meaning, that’s why the government can just issue as much currency as it needs.
Many of the billionaires are complicit with members of the party, obviously, sharing the money with those in power in order to do what they please.
If that was the case in practice then they wouldn’t be fleeing China to go to places like US where they can do as they please.