Windows doesn't matter to Microsoft now. The big sellers are Azure and Office 365 and they work on Macs.
As for market share in the US, I very much doubt it's that high really. There are huge unimaginable swathes of windows boxes which won't show up in GlobalStats at all. I know a company with 50,000 desktops that can only visit a web site on an internal network for example. Those sorts of installations are everywhere.
I already see this situation with Google, where non-technical folks will push back on choosing Google products even if they are the only credible player because of the perception that Google cancels everything and they don't want to be caught out.
Microsoft is playing with fire if they think that screwing with their customers computers will have no repercussions with other products.
They've build up enough political capital to expend it, upset their customers, and normalize all these dark patterns. They're taking the risk that 5 years later everyone will consider these things common and not be bothered by them. Apple did the same thing by making an attractive ecosystem. Windows is using its dominance as a platform to make the same exchange.
