I mean, if I could just get a nice Maemo Phone I'd be happy, like throw that on a Lumia 920 and I'd be content. There is definitely room for innovation in the mobile space, and both MS and Nokia have the hardware side of it down, they just need to choose a platform that people can get behind and make it easy to move to it (eg. have a preinstalled app compatibility layer).
I have trouble believing that a 90%-10% duopoly in mobile platforms is an healthy steady state for this market.
Probably something else - not as good - will come in and occupy the vacuum.