Re: it is not the customer's job to adapt
"People stayed with the older Office versions for many years (because of their superior usability); other people switched to alternative software with a better UI (such as Libre Office for one, but there are others, and I probably should mention the Google products too here, though I can't say anything about their UIs 'coz I've never used them) and to this day do not use the damn ribbon. Other people again switched to or stayed with competing commercial products, notably Word Perfect and Quattro Pro."
Yes, I am sure that many people who had the choice and the technical knowhow either stuck with old versions or switched to something else. However the market share of MS Office vs all other offices, and of new vs old MS Offices, show that those people are still in a small minority. The majority of people using Office do so either at their workplace where they have limited control of software provider and Office version, (which gets pushed by central IT), or as a package when buying a new PC, in which case they will get whatever version is given them.
"The rule is customer fella pay money, supplier fella adapt."
It is, in a normal market. Microsoft Office operates (even now, with all the Libre alternatives) in a quasi-monopolistic market. 10 years ago, even more so. And it's amusing if you think Microsoft Office's customers are private buyers or individual users of Office. The customers are those who pay large amounts for large volumes, meaning big corporations and specifically their mid-level IT managers, pointy-heads who are easily swayed by MS event presentations and shiny-shiny rather than by the concerns of their users.
Please note I'm not saying that MS was right to introduce the ribbon, nor am I arguing about which is the superior interface. I'm saying the world has moved on and there's no point flogging a dead horse.
Biting the hand that feeds IT
