I doubt that Mears made much money on that setup. Truth be known, I wouldn't be surprised if the contract ended and Mears adjusted the cost to Disney upward quite a lot because they weren't doing much but breaking even, if they were lucky.
Think about it, planes fly in and out of MCO all day long and the primary reason is because people are going to Disney. Buses like the ones used would cost in the range of $500k+ each. I'm not sure if they ran on a regular circular route, but it required at least four running all kinds of hours, paying drivers, buying fuel, tires, regular maintenance, staff to keep the buses clean and pristine. Field supervisors that are needed to be watching over the operation and being within reach to take care of problems that inevitably come with dealing with the public and adjusting for traffic in the area.
Those buses don't just drop down from heaven to be there so every single rider doesn't have to wait an unreasonable time to get that ride. Mears did continue it (I'm not sure it is exactly the same schedules) for a fee, maybe somebody that used it can tell us what it costs to use the Disney themed Mears buses now.
Anyway, since Disney has now targeted a new audience consisting of Upper middle class to filthy rich, they are coming up with a group that can afford a stretch limo, with Champagne, luggage handlers and not have to share a ride with a group of strangers. It worked to their benefit early on and with time and the right price, Mears will seamlessly take over that chore and headache and Disney will just enjoy the profits created by no providing that service. Something they are doing now quite happily.