Apple is already running on top of Linux
Kinda sorta maybe. From Wikipedia: OS X is based upon the Mach kernel. Certain parts from FreeBSD's and NetBSD's implementation of Unix were incorporated in NeXTSTEP, the core of Mac OS X.
Although I used to be a heavy apple user (back in the 80's), I have very little recent experience. But, it seems to me that Apple has worked hard to support their hardware. They limit what is available (limit your choices) and that means that you are far less likely to have compatibility issues. Not always true I am told, but mostly so. So, you pay a premium for it, but you certainly get something in return.
On Linux, I can find an application for almost anything and simply say "install that". I happen to really like a lot of what I can simply install and run.
On the other hand, Windows has more of certain types of applications; for example, tax software and the latest games.
For sure, Linux seems to run multiple virtual machines much better than Windows. I have not done this on MAC so I cannot speak with authority on this, but, I understand that it does a good job (by good I mean better than Windows and no comment on Linux or Mac being better).
I haven't done it lately but Windows ran pretty well in a Virtualbox VM under Ubuntu. It seemed like not all that much of a performance hit for common uses. You would have to pay attention to Windows licensing. I believe that some Windows versions cannot be run as a guest O.S. but I'm not at all versed in such matter.
I know for certain that Linux was way more stable than Windows, but Microsoft seems to have improved significantly in this regard. I find that some of the video drivers on Linux can be a bit flaky. I used to find the same on Windows, but, they were still usually more stable than the Linux video drivers.
The Nvidia drivers for linux seem pretty stable. ATI/AMD used to be a problem but I believe that has improved lately.
Oh, and my opinion is that Microsoft creates the best Visual software development environment, but, again, that is just my opinion.