Try managing a directory service even on RedHat and see how it goes.
I... get it.
The FAANGS needed to scale to a level where paying per-core licensing fees for an operating system was simply out of the question, not to mention the lack of customisability.
As a consequence, they all adopted Linux as their core server operating system.
Then, as their devs made millions in share options, they all scattered and made thousands of little startups... each one of which cloned the assumption that only Linux was a viable operating system for servers.
The mistake here is the same one that caused "Only MongoDB is Web Scale" and "Microservices are necessary for two devs and a PC as our server".
Just because a trillion dollar corporation decides on a thing, it does not mean it applies universally.
Outside of this bizarre little bubble, Windows is everywhere and Windows Server is still about 50% of the overall server market.
Operating systems and other applications that demand per-core licensing fees exist only because the people who buy them do not use their own money for this, so they do not care how much money they are wasting.
Most companies waste huge amounts of money not only for software, but for many other things, because those who have the power to make purchasing decisions have personal interests that are not aligned with what is really optimum for the company, while those who might have the best interests of the company in mind do not have the knowledge that would allow them to evaluate whether such purchasing decisions are correct.
The survival of Windows Server is not justified by any technical advantages. A few such advantages exist, but they do not compensate the huge PITA caused by licensing. I worked at a few companies where Windows Server was used and replacing it with either Linux or FreeBSD was always a great improvement, less by removing the payments for the licensing fees, but by providing complete freedom to make any changes in the environment without the friction caused by the consequences that such changes could have in modified licensing fees.
Past a certain scale I would agree with you.
> the friction caused by the consequences that such changes could have in modified licensing fees
Your experience is uncommon.
In most corporate settings the IT staff never think about licensing because there is some sort of Enterprise Agreement in place.
In my work the only exception to this is SQL Server, which got stupidly expensive over time while falling behind in features.