These people still have to eat. They have to live somewhere. They still buy things. Often gaudy, awful things and other disgusting displays of wealth, but things nonetheless.
That's where you get them.
Oh, what's that? They moved out of the country? Well then, they're not there to stop the country from nationalising their stake in whatever part of that company exists in that country, are they?
Anyone acting on their behalf to stop that should be taxed on their behalf. They won't pay their human sock puppets? Don't be a sock puppet then.
If they want their stake back, they need to live in the company's host country (because there's always a main HQ) for one full tax year.
They own multiple stakes in multiple companies in multiple countries? Sucks to be them, I guess. Shouldn't have been so greedy.