LoudMusic's answer is completely correct.
Think of what a terminal means, and expand your notion outwards - a terminal could be an electronic piano, or it could be a digital thermostat, or it could be a hacked appleTV. Each of these things interfaces with the operating system directly, and none of them require a console GUI. I'm quite fond of remote desktop, which lets you use a headless machine as though it had one, using someone else's head. Watching media off a remote server is a similar example - there's absolutely no need for there to be a GUI.
In the rare cases where a GUI is required to maintain or repair an operating system, then the VM manager always provides a method to access it. The interface is usually cumbersome - like watching a favorite movie on a hospital heartrate monitor - but is always enough to let you get the job done. However, some VM managers provide a console that is fully usable, even running in full screen mode with full motion video, 3D, and audio capabilities. These products are very mature and cater to nearly everyone's needs.