Graphics and UI are a function of the people developing the upper level interface. They are not a function of the underlying OS unless the software stack is in some way fundamentally broken and, at least WRT MeeGo, it is not.

Mainstream consumers may not, but device vendors may. After all, Microsoft is basically throwing their weight around in the design of these devices, and both WP7 and Android make the hardware vendor play second fiddle to the OS vendor. With MeeGo, they have an opportunity to brand themselves without annoying the OS vendor.

And the whole "but the mainstream user doesn't care" argument is dangerous, since it justifies lots and lots of things that generally aren't good. You know, like forcing DRM on people (who don't know that it's enforcing restrictions on them.)