You used to be able to do everything on a computer.
Now the computer does everything for you.
In my opinion, a consumer OS is an OS that does everything for you- with little or no option to change the default behaviour. A non-consumer OS goes out of it's way to offer you power and expandability at the expense of simplicity.
NeXTSTEP, OpenStep, OS/2 Warp, Windows 3.1 through to 7, BeOS, Linux, Free/Net/OpenBSD are non-consumer OSs.
Mac OS X and Windows 8 are consumer OSs. They sacrifice usability and options for bling and simplicity.
-SC