Username or EmailPassword
You say people turn on their computers to "get things done", yet complain that features that enable getting things done are "bloat". dbus is tiny and enables processes to talk to each other. Would it be better for each application to implement it on its own? Of course not. Apps depend on it because they need it, just like applications written for RISC OS depend on features of the RISC OS. The only reason why you don't experience dependencies as a "mess" there is only because you don't attempt to rip out core OS features of a closed-source OS.
As for UIs changing between releases, that happened with RISC OS as well. If you don't want change, don't change. But you can't really use RISC OS as your primary platform today.
Except the RISC OS UI really hasn't changed much at all between RISC OS 2.0 and the latest RISC OS 5.19 in development, so that's 24 years.
The differences have been in skinning, basically, and not only that, but the default skin that 3.5 and later have used, is available as an add-on for 3.1x.
Today's Linux desktop environments, along with Windows, give bigger changes in UI available in the SETTINGS DIALOGS than RISC OS has had in 24 years.
Looking at the screenshot of Arthur ( http://en.wikipedia.org/wiki/File:AcornArthur110desktopsmall.png ), the overall model of RISC OS UI even seems already more or less set at this point? (but of course dropping the obnoxious colour scheme)
So that would be 25 years. Either way, basically quarter of a century.