Now that's scary.

One of the reasons the smartphone market was not as big as it could have been in the US earlier may have been because manufacturers were making US service providers happy. The service provider is the device vendor for most US customers.

Enter the iPhone and now any Android device and look over in the corner, grandma seems to have a smartphone too!

In the US this seemed to come about once Apple had a product that was compelling enough so that their terms could be dictated to the service provider in exchange for exclusivity. Google then created free services that the service providers customers want but for an exclusive period of time, are only available on the Android OS.

I really hope I am misreading the intent of your post, because it sounded like to me that MeeGo is being designed to give these service providers the ability to lock out selected services until additional fees are paid by the user.

WAP, J2ME, and MMS are examples that come to mind of that approach and they were all designed by "device vendors" to make their true customer, the service provider happy.

EDIT: I also just realized that you could be talking pure hardware and in that case new development could be stifled by the limitations of these existing OS's. That is, a new technology could wither on the vine if Apple or Google do not plan to support it.
In that case an OS that is modular and can be scaled up or down depending on a vendors needs would be a huge advantage.