Why switch from a tested kernel that is technically very nice? Nothing about the kernel prevents proper support of POSIX and it has a lot more drivers and hardware support than any existing kernel.

Your exposure to the kernel in the last 8 years is not representative of 90+% of computer users.

Unless you're OK with breaking compatibility with all existing Windows apps - most of which you have no control over - rewriting the kernel as a POSIX thing is going to look a lot like 'bash on windows' in reverse. You'd have to have some kind of shim layer to translate all the old system calls, so most everyone's existing software is going to be slower and there will be bugs, etc. Including your own, since Windows is a kernel, a ton of drivers, a userland (including basic runtimes), a windowing system, a basic set of productivity tools and games, etc.

I think this would be a total disaster that killed Windows, personally.

The kernel isn't that import but all the software that depends on it and the win32 libs is. There is lots of software that is w32 only, more then enough to keep windows around for years.

There are thousands, probably millions of small business critical pieces of code running on systems all over the world running more than just .NET code. You'll have to emulate or recreate nearly the entire operating system, at which point... what did you accomplish? Businesses are going to compare the cost/benefits of upgrading their OS vs upgrading some old code, and decide it's not worth it.

Perhaps you've been lucky enough to move to more modern systems, but you're in the tech circle. For everyone else, it's not an easy option. Have you ever worked for a fortune 500 company? There are systems that are nearly 20 years old with billions of dollars running through them. Moving that is not a light decision.

That's the thing. There are many things that are really important that don't actually touch every single person on the planet.

One of the most widely used OS's ever is called Tron. Does that effect me? Not really. Is it important? I think so. I thought so at least enough to do some reading on the subject. Was it important from a CoSci standpoint? Maybe. NT is important from multiple angles, as well. Also, it's importance doesn't take away importance from the things that may actually touch your life. Such is the nature of things.