I think your missing the point, of cost of doing business, with the direct cost, sure you can go to another phone company for your service, but the unit rates will remain the same with that company, and the same goes with your vendors, you can change a vendor, but every price he quotes you will pass on to your customer.
You have a phone company now, what are you going to do move to another company every time you deal with a customer?
Or change your yellow page Ad. after it is published and get a better Ad rate?
The State makes the laws that controll the Worker comp insurance rates, you can run to a hundred brokers, but the rate will remain the same.