And, there a definite feature differences in how the kernels behave, so they will have to rewrite major sections of Windows to fall in line with the Linux way of doing things.
And on top of that they will have to support Wine, or their own equivalent of it. In order to make decades of Windows only applications work. Sure Wine works pretty decently now, but not at an acceptable level.
They appear to be working on getting Direct X to work on WSL, but not sure how that will work if its on raw Linux. I don't think it does.
And Windows handles drivers completely differently than Linux. There was a thread here in the last few days about the AMD drivers being ~10% of the lines of code in the Linux kernel. There is all kinds of specialized hardware that take advantage of Windows drivers. Which would now probably need to all be in the Linux kernel.
And how about Active Directory? Thats a huge part of the Enterprise use of Windows. Need to translate all those features and controls over to Linux too.
So even if you save a few Engineers on the kernel dev directly, you probably have hundreds of new jobs to deal with the migration. If not thousands.
This is really anecdotal, as I sadly did not find the article I have this information from, but IIRC, the core NT Kernel team isn't as big as one would expect, about a dozen to two dozens maximum (big emphasis on "if I recall correctly").
Also I believe Microsoft employs somewhere around 50.000 engineers, a good amount of whom work on and maintain low-level systems. I find it unlikely they'd have a shortage of sourcing talent for one of their core projects.
If the NT kernel is in maintenance mode that might be because they are planning on replacing it.
> Obviously Windows isn't going away - but how many of Microsoft's customers would know that their kernel has been swapped out when the UI and all the applets look identical
Right. Because it's just a simple switch to flip when changing kernels, and all of the Windows software will just go on working as it before.
On the flip side as Azure becomes more significant for MS the role of Linux becomes more significant. At some point the cost of working on two kernels is going to outweigh the benefit of transitioning Windows over to Linux.
Or maybe not. It's hard to predict things. Especially about the future.
Obviously Windows isn't going away - but how many of Microsoft's customers would know that their kernel has been swapped out when the UI and all the applets look identical? As far as they're concerned the switch could have already happened! All they care is the look-and-feel is the same and their applications still run. They don't care about the kernel.
It's not a matter of better, it's a matter of good enough and saving on expenses. Presumably those engineers could be better utilized somewhere that's generating more revenue.
That's the bottom line.