Unity is only one option in the Canonical stable. Users with older systems
or those that duo not want to chase trends can use the LTS and use a less
powerful desktop. Unity runs on a netbook with 1gb of Ram just fine. The
problem that will affect most users will be having compositing and getting
the right graphics driver.
Ubuntu has always had a fascination with being on the bleeding edge. The
move to Unity and later Wayland confused some observers, but if you
understand Shuttleworth and his vision it should not surprise. They are on a
mission and have been for some time.
They may leave some users behind initially but once people get it they will
be out front.
What Unity achieves is more choice and even of you don't use it.we still
benefit.