This one I can possibly answer. In my opinion the megacorps have a whole lot of economical leverage over states and governments. Sure, the megacorps produce their goods, but they're bound to use some local suppliers for parts - for cost efficiency. If a national government were to anger them so substantially (and barbed wire does that because it erects all kind of discomfort for the corp citizens - they might realise the prison they're in), a megacorp could put down a boot and get those parts from elsewhere. Sure, it#ll cost more, but not that much, and they can afford to teach the local governments a lesson. This'll hit the local suppliers, and hard. They'll go bankrupt in two months flat if their main customer stops buying. A lot of middle sized local machine shops/factories are bound to one customer.
So, people will lose their jobs which means losing popularity and there will be less taxes to derive from. The megacorps won't pay taxes to their host country either way.
What's the net gain? Because this seems like a loss to me.