Billionaires are billionaires because of the extreme disproportionate gains by the few at the expense of thousands/millions.
They're used to seeing the many slave away for their interests.
Not seeing that happening now is throwing their view of proper world order into chaos and they're not used to be back in a position without control.
There's nothing non-capitalist or non-free-market about a worker collective. There are no laws against it. Nobody will try to stop you. You don't need a change in the government.
What are you waiting for?
I mean, people say a lot of horseshit about what capitalism is or isn't ("I'm a capitalist because I'm for making money and profits.", etc), or creating a fake context where the only alternative is ownership by the state.
But at the end of the day it's about the worker employer relationship, period, end of story.