Here's the thing though, the desktop now really is about power users or corporate users, because everyone else just uses cell phones or tablets. So ok, sure, your sales people and your secretaries probably aren't going to care about the control panel, but people that use computers outside of work are mostly going to be power users and they're starting to have options. (I can use all the software I need on macOS, and linux is rapidly getting there too)
And honestly, breaking Printers is a thing that everyone is going to care about, especially people in a workplace.
As explained above this is irrelevant to enterprise users, corpo installs don't play with per-station configuration like this or care about consumer-facing UIs, the needs of that market revolve around things like image management, deployment, and active directory administration.
You're right that the home market is shrinking though, the OEM install market is down billions in revenue and has been dropping by double digit percentages each fiscal year, but you're wrong in your assumption that the power user market is worth anything. Power users, represented by direct license installs, are a rounding error of Windows revenue. There's nothing worth fighting for there.
Convincing Mom that she should buy a Windows laptop instead of an Apple laptop is still worth ~$750M/Q, and Mom doesn't ever want to see the old Windows panels, she loves the "Add Printer" button. Convincing Timmy Q Hacker that he should buy a Windows license key instead of installing Arch Linux is worth squat.
I think you're overestimating the importance of the revenue generated and underestimating the importance of mindshare and people caring about their system. If the next generation of creators (IE, coders, designers, etc.) grow up on macOS and linux then Microsoft has a real problem down the line. The Windows monopoly has been VERY good to them, they would be foolish to lose it by angering their most passionate users even if in the short term they don't see an effect on their bottom line.
> I think you're overestimating the importance of the revenue generated
It is literally impossible to do this. Revenue is the only thing that matters when measuring markets. If it doesn't affect the bottom line, it does not matter.
Passion does not sell OEM installs or license keys. Creators and hackers didn't buy MS products in appreciable numbers to begin with (compared to consumer and enterprise markets), so to the degree MS can be said to be losing them, MS does not care. If moms and humanities majors stopped buying laptops entirely and that $750M/Q dropped to the ~$1M/Q the power users drive, MS would probably pull out of the OEM license market.
This is a very different mindset about how businesses operate than you seem to share, which is fine, I'm explaining it not trying to convert you to it.
You are certainly right about revenue. You say you are in enterprise IT, I used to be there. I actually built and was responsible for the IT of one of the few larger "Linux only" enterprises in the mid-2010s in Germany (like you said, Fedora and Gnome2. Ubuntu and Gnome2 for us). When I left we were talking about a 1000 seats. Needless to say, it worked mostly flawless. Yet we always had the same "battle" with new joiners, unfamiliar work environments. We had to move accounting (20 seats) to MS Windows so that accountants would come to work for us. No matter that the 20 seats caused three times the support compared to the Linux seats, no accounting is still worse ;)
Anyhow, that's what Microsoft is abandoning. Familiarity. If young people do not learn MS Windows and MS Office during school or at home, the grip on the enterprise will vanish. We already see it in tech-oriented departments, where Macbooks reign supreme. I for one wouldn't like to use a Macbook, but I sincerely hope that MS grip on enterprises is broken sooner rather than later.
And honestly, breaking Printers is a thing that everyone is going to care about, especially people in a workplace.