The Prime universe didn't go anywhere. It's still there. There are still novels and comics. You can still buy the DVDs and Blu-Rays. Thanks to La-La Land Records, Intrada, GNP Crescendo and Varese Sarabande, you can get the soundtracks (and in many delightful cases, remastered, updated and even core inclusive expanded sets.) The fan films exist, and some of them are desperately and viciously advocate for the Prime universe.
This whole dead-horse-beating of bringing the Prime Universe back is dumb. Not as dumb as the rage over lens flares or the fan erection over how allegedly badass Robau was, but still... dumb.