Fundamentally, I wonder if Microsoft has lost the "spirit" for Windows.
If you said "where do we steer Windows for the next 10 years", I'm not sure there's a great answer, one that would please business people.
The right answer is probably "as a platform, it's on auto-pilot. Focus on preserving customer workflows, encouraging the growth and happiness of power users (who are stickier), and general cleanup/security/tech debt retirement. Above all else, don't give people a reason to think about an alternative." This was their message for years. We won't break your ancient badly-behaved apps. Your muscle memory will work. All those little customizations and weird shareware tools that let you pull more performance out of the system are encouraged. But that's a message to your existing customers, not something that pulls in new ones.
Microsoft has never been particularly good at getting Windows outside of its desktop and x86/x86-64 niches. They lost interest in all the old platforms (Alpha, PowerPC, etc.) decades ago, and then finally came back with an ARM attempt that seems to target a handful of weird machines nobody can actually buy. Their attempts to get away from the desktop paradigm either failed (WinRT, WinPhone), or found a niche and stagnated there (WinCE). TBH, I'd sort of blame Intel/AMD/VIA here in part: there was no useful x86 response in the low-power space, so many appliance-computing markets were just left entirely to MIPS, ARM, and RISC-V. If you're already committed to an entirely different architecture, why bother with the Windows APIs, which may not be as bulletproof as on x86?
By moving stuff like Office to web-based and Electron apps, they undermined the platform value of Windows. If Blink is your actual runtime, then it's much harder to say "Your day-to-day desktop workflow is so much better on Windows."
By constantly moving people's cheese and enshittifying the product, you get people to ask "what do I have to do to get an ad-free experience, or a shell that isn't actively fighting me every step of the way"-- conversations they should never be having, and which provide a bat-signal to draw the Mac and Linux acolytes in.
Eventually, the primary selling point for Windows is support for closed-source software that fits into a narrow sweet spot: too hostile to run well in WINE, too demanding to put in a locked-down-forever VM. That seems like a market that's both getting smaller by the day, and very difficult to grow.