Ran into the old Marc Andreessen quote from 1995, Netscape will "reduce Windows to a set of poorly debugged device drivers".
Remarkably apt. Mobile and the competition and especially the web have stripped the primacy of the desktop OS way back. There's mostly just inertia, a lot of legacy, keeping Windows moving forwards. And that legacy, as we keep seeing, is not that radically difficult to emulate or translate. The gui itself has expected behaviors, but I would not say they are loved? There are like 4 different sound control panels in modern windows. The legacy has kept piling up, but in a way that has never become more distinct, or more meaningful: it's chaotic & senseless. Whereas folks like Gnome can ship a radical 3.0, some radical shifts in their long 3.x series, and then go build a 4.0.
Beyond comparison to other gui computing systems, the greater trend wiping Windows relevance off the map is the cloud, is that we no longer want to care about individual computers & computing in isolation. Where we want to go today is across a panoply of systems, into a highly networked well connected cloud, albeit clouds that in practice have been alas radically infantile in ways ("Internet of Shit"), lacking much of the "PC-compatible" spirit of portability & consistency that supported & enabled the rise to the desktop. None the less, Marc has ended up being pretty spot on. Computing is multi-system, multi-device, computing is connected, & we expect most of our experiences to have online impact & usability: this is something that Windows has never really adapted to, never rebased around, despite attempts like Microsoft Live, Microsoft InfoCards, Microsoft OneDrive.
This Andreessen quote also highlights what Microsoft would gain by switching to Linux: far better debugged drivers. Instead of needing to write a Driver Development Kit (DDK)/Windows Driver Kit (WDK) with a bunch of ideas & hope people pick good ways to use the DDK & build robust support, sometimes stepping in themselves if they are desperate for better support. Often it's up to OEMs to fight with their hardware vendors to make the stuff work right. Where-as on Linux, best practices for devices drivers can evolve organically: as one device drivers learns & adapts & figures out good ways of, for example, playing sound, other device drivers can adapt & follow the lead. Common patterns can be surfaced & enshrined. The kernel is it's own documentation for how to move forwards, a nearly complete corpus of what it takes to compute. Windows on the other hand inherently lacks this ability to debug, to find sense for the developers on the platform, for those developers cannot relate with one another: they can only relate & share with Microsoft, whose time & support is limited.
What is Windows's purpose for existence? It reached such vast heights, but now what role does it have, what mission does it have? It's meaning is degraded by a world where devices are now, as Marc pointed out in 1995, terminals to a greater world, & it's distinction among operating systems is fuzzy, uncertain.
As this Chris Wilson's key "History of the Web" slide title declares, "The Web as universal platform"[1] has largely become true (among other erstwhile desktop competitors like native mobile apps). If Microsoft can gain better technical underpinnings, that is easier to support & make fast, by porting their environment & their platform APIs on top Linux, then they can perhaps better focus on finding real distinction & advantage for themselves, finding ways to reach out & regain relevance & connectivity from a more share-able, embraceable, knowable, & connective base (Linux). I think it would be a great advantage to Microsoft to build themselves atop the known & adoptable, with better drivers, better subsystems, & it would be better for us the consumers by far measure. This is why I think, although unlikely, Microsoft should rebase onto Linux.
[1] https://www.youtube.com/watch?v=KRE9S7B-DV8#21m10s