[mmx1]

Obviously we'll never know, but I seriously doubt that parallel universe would've had a chance to materialize. Not the least due to "free as in beer" aspect of Linux whilst web/Apache was growing at the pace it did. All proprietary unices are basically dead. Sun was likely the sole company that had the best attitude to live alongside open source, but they also proved it wasn't a good enough business post bubble burst. NT and Darwin remain alive due to their desktop use, not server.

[skissane]

IBM z/OS is officially a Unix-a very weird Unix which uses EBCDIC-but it passed the test suite (an old but still valid version, which makes it somewhat outdated) and IBM paid the fee to The Open Group, so officially it is a Unix. (Although somewhat outdated, they recently added a partial emulation of the Linux namespace syscalls-clone/unshare/etc-in order to port K8S to z/OS; but that’s not part of the Unix standard.)

If Microsoft had wanted, Windows could have officially been Unix too-they could have licensed the test suite, run it under their POSIX/SFU/SUA subsystem, fixed the failures, paid the fee-and then Windows would be a Unix. They never did-not (as far as I’m aware) for any technical reason, simply because as a matter of business strategy, they decided not to invest in this.

[pjmlp]

With Microsoft having either Windows NT with proper UNIX support, or real UNIX with Xenix, there would be no need for Linux, regardless of it being free beer.

Whatever computer people would be getting at the local shopping mall computer store already had UNIX support.

Lets also not forget that UNIX and C won over the competing on timesharing OSes, exactly because AT&T wasn't allowed to sell it in first place, there was no Linux on those days, and had AT&T not sued BSD, hardly anyone would have paid attention to Linux, yet another what-if.

[p_ing]

NT underlies the majority of M365 and many of the major Azure services. Most F500s in the US will have at the very least an Active Directory deployment, if not other ancillary services.

IIS and SQL Server (Win) boxes are fairly typical, still.

[mmx1]

I am not suggesting NT is dead on servers at all. I am positing it would be dead had it not been for owning the majority of desktops. Those use cases are primarily driven as an ancillary service to Windows desktop[1], and where they have wider applicability, like .NET and SQL Server, have been progressively unleashed from Windows. The realm of standalone server products were bulldozed by Linux; NT wouldn't have stood a chance either.

[1]: In fact, Active Directory was specifically targeted by EU antitrust lawsuit against Microsoft.

[throwaway2037]

For all large corps, users sit at 1990s-style desktop computers that run Win10/11 and use Microsoft Office, including Outlook that connects to an Exchange server running on Windows Server. I'm not here to defend Microsoft operating systems (I much prefer Linux), but they are so deeply embedded. It might be decades before that changes at large corps.