They have just decided to sell all their stuffs on all their places, instead of pushing Windows. PCs are losing their place so they've decided not to go down with the ship. But, they have no need to replace Windows, that's still a large bastion of sales for business, and a tremendous lead in for Azure and Office 365. That would only lessen if they moved to something they controlled less.
Microsoft makes a pretty good amount of money on Windows licensing, and a whole lot of places run Windows because 1) AD is pretty great, and 2) A lot of software businesses rely on is Windows only.
I do not see this changing in the near future. I can't see a strong incentive for companies to switch to Linux even if MS brings AD, GPOs, Office, and its own MS-supported WINE.
AD is not great. It depends on a legacy model with trusted company networks that was out even before COVID and all the home working hammered the last nail into its coffin.
Setting up new systems with it remotely is a real pain, something the EMM model fixes completely.
Pretty much all the remote work I'm aware of in my area is done using RDP, so AD is still relevant. I think your opinion may be biased towards smaller and younger companies.
I work in EMM (though not Windows) and we are rapidly moving to Intune/Azure AD now because of this change. Onboarding new machines has become a nightmare when people can't go to the office.
The problem is a catch-22.. We require a 'trusted' machine to connect to the VPN. Yet the VPN is required to connect to AD and bind it, which is the de-facto way it becomes trusted.
Before someone in the office would do this but in many cases this hasn't been possible since COVID so it's exposed the issues with this approach. But even before that, working from home has been causing a lot of friction.
Everyone is moving to EMM models now, like Google Beyondcorp. MS is pushing Intune now as main management, with 'comanagement' with AD for the time being because it doesn't have the same scope of functionality yet. But it's clear that their long-term plan is to abandon it.
The problem is that if they offer anything but 1000% bug-compatibility, a Linux-based Windows is just another Windows RT-style penalty box. Yeah, it runs Edge and Office, but none of the closed-source line-of-business software that are baked into people's refined-over-20-years workflow. None of the games with such aggressive and brittle DRM and anti-cheat they break under even official Insider builds. None of the drivers for obscure peripherals that the manufacturer disowned by 2010. You still have a sky-high switching risk.
The way out I could imagine would be some sort of packaged virtualization, like the "XP Mode" feature on Windows 7. Your legacy apps spin up in a thin, well-integrated VM which ran a "final" build of classic Win10 designed for minimal disruption. The VMs, in turn, would be aggressively sandboxed and firewalled to keep it tamed. I'd suspect there'd still be some gaps-- drivers for hardware that can't be easily wired to a VM, but I suspect there's a mountain of logistics and performance issues that don't fit in a two-paragraph post.
Most of these decisions are driven by cloud computing where the data servers are primarily running Linux. To get the developer mindshare they have to provide their products on Linux. In the case of Edge, it was to allow testing for browser compatibility on a Linux CI environment. Same thing with WSL an VScode.