If they started to charge, wouldn't local competitors just spring right back up again?
I guess it depends how the local competitors went out of business (and maybe some local laws). If they crashed & burned and directors were declared bankrupt, then they may not be able to start another company for 'x' years. If they liquidated their assets, then maybe they can't raise capital to buy new infrastructure again.
It's not as cut and dried as going out of business, waiting for circumstances to change, and then going back in business.