Regulatory Capture and Washington DC taxicabs

I flew to Washington DC's Dulles airport a few days ago. The airport is something like 30 miles outside of the city, and there is no metro service to/from the airport, so taxis and shuttles are pretty much the only choices for getting into the city if you don't rent a car. I took a taxi, and realized that the system serving Dulles is truly messed up.

Specifically, for regulatory reasons, only one company is allowed to pick up at Dulles airport, and that company is not allowed to pick up in DC city limits.

The airport actually highlight the fact that only this one company is allowed to provide taxi services, as if it's some sort of benefit to the traveling public. But this seems to me to be a total scam.

After all, these rules mean that each fare from the airport to DC must return empty to the airport, and each fare from DC to the airport must return empty to the city. As a result, taxis are consuming twice the necessary fuel for each passenger, are losing revenue-generating opportunities while dead-heading (it takes more than a half an hour to get between the airport and the city if there is any traffic), and are making traffic that much worse by the fact that twice as many taxis are on the road as are truly necessary to serve the round-trip passenger traffic. Fares, as a result, are undoubtedly higher than they need to be to compensate for these expenses and inefficiencies.

What we have here is a case of regulatory capture, which usually at least serves the interests of the industry that provides the relevant service. (See another example of this in Louisianna, where regulatory capture protects the funeral business.) But here, it seems to serve nobody's interests, since this cannot possibly be good even for the taxi drivers who must dead-head one-way for every Dulles passenger.

I wonder why this insane policy continues at Dulles.