Almost all the documentation and best case expects Macs to be tied to an Active Directory / MS environment for management.
As a typical Web / LAMP host, OS X really is not that performant. Unix tools execute faster on a RHEL/CentOS box then an OS X (even if the OS X box has higher specs). MySQL is particularly bad if it hasn't been tuned, and most of the literature seems to indicate that OS X (or more specifically MACH) doesn't have the level of optimisation for server workloads.
That being said, if your using the OS X frameworks, there can be some great value with exceptional performance (just look at the startup using Mac Pros as image manipulation servers).
Now with the move of things into just the app bare bones style docker VM's in which the app is a service upon a server then maybe some form of runtime that enables some applications would be useful, maybe.
But if they went into the server market, then the trust of doing partnerships with server focused vendors would diminish. Though VMWare would probably be just as happy, if not more and that would be about it. IBM, for the arrangements they have now, work for both of them too well to upset I feel.
Render farms have largely been supplanted by Linux, and studio networking can either be handled by a Mini on the shelf or a Windows server in the closet.
Still they do like consumerising things and who knows, personal home iCloud that sits in your home would perhaps be a likely server offering if any they may take as targeting consumers. That if any route is maybe the one that could happen.