Run VMs of Mac OS X Server... on what hardware ?
Apple already has a deal with VMware to enable virtualization of OS X Server. We can already run OS X server in a VM. However, that doesn't change the fact that it needs to run on top of Apple branded hardware (ie, the Xserve).
There is no more server grade Apple branded hardware.
As for the poster you're replying to, his comment made no sense. If someone was a OS X Server admin and only that, that guy was already pretty much incompetent. Good systems administrators know the basics of how a system works and can adapt easily to any system out there. Unix is Unix, hardware is hardware. It all works the same, give or take a few implementation details. If you have the basics down, the rest you can pick up as you go.
Same for programming. If you're a programmer, it doesn't matter what the "language du jour" is. You know conditional statements, you know looping, you know variable typing, you know pointers, you know objects. The syntax you can pick up.