Re: "The OS companies have insulated themselves from user pain"
I've always assumed that having been forced into the corner of standardising file formats MS couldn't keep up their usual trick of evolving them so as to force any would-be compatible S/W to be in perpetual catch-up mode. Instead they forced their users to learn a new UI whether they wanted to or not so that in a few years all the ribbon-native users would find it harder to transfer across the compatibles. Or at worst, it would force the developers of the rest to play catch-up on UIs.