Cab companies agreed to those rules in exchange for the privilege of picking up random hails off the street. That used to be an enormous competitive advantage over competing transportation providers (e.g. SuperShuttle, limo services, etc). Thanks to mobile phones, that's no longer a significant competitive advantage. Everywhere that Uber operates legally though taxis have the option of giving up that privilege in exchange for being released from those regulations (essentially becoming Uber). Nobody is forcing taxi companies to stay in the regulated taxi business.