I'm sure those running web servers, super computers & ATC consider it a hobby OS
I specifically mentioned desktops, saying nothing of servers.
Linux is fine for servers, although real UNIX or (in some cases) a mainframe would be even better.
Sounds like you've opted for solutions that rely entirely on Windows so are locked in.
I have more than a hundred applications installed on my computer, and only a handful of them exist in versions for any operating system other than Windows. If I used a Mac, almost all of these applications would not be available to me, and the situation would be even worse with Linux. Since I base my choice of operating system on the applications I wish to run, Windows is the logical—arguably the only viable—choice. Not only do these applications generally not exist in versions for any other platform, but there are no suitable substitutes for them on any other platform.
This problem is painfully obvious for people who must use desktop machines for productive work. It is often not at all obvious to people who are more interested in playing with an OS than with getting real work done. Two different user communities.
If you were in their shoes, would you not attempt to do the same?
No. I have been in similar shoes, but I have not done the same. I have a conscience. Asking people to pay money for something and then disclaiming responsibility for everything except a tear in the cardboard box in which I provide the product is not ethically tolerable to me, and enforcing such a lopsided contract could be problematic.
The London Stock Exchange share trading system, TradElect. That was running on Windows 2003, with .NET and C# programs written by Microsoft and Accenture.
It amazes me that anyone would be stupid enough to try to implement systems of this kind with Windows, .NET, and other such junk. I can understand why Microsoft and Accenture would push it, because that's what they have available, and they don't really know anything else, but the client at least should have done the research necessary to avoid this mistake.
Mission-critical enterprise-level systems are best implemented on mainframes, but a whole generation of so-called IT experts has grown up without even realizing that mainframes exist, so naturally they are too naive to see their suitability to this sort of application.
Being replaced by a Linux based system.
So they still don't know what they are doing. Hopefully they'll be able to squeak by with Linux, if that be their desire, but again, a mainframe is the proper solution. It's expensive, but you get what you pay for.