Zuffa dominates the market, and make it a point to erase him from history. Over time, he won't be known unless fans keep him in the mix, but when he starts to get discredited more and newer fans never learn his name or just know what Dana has said about him, he won't last as a legacy. Not that I want that, that's just how it works.
I didn't know who he was, until recently (by fan standards). I had never heard him mentioned. I looked into it myself. And after doing the research I see his skill and he was very impressive. But to the every day, watch UFC when it comes on fan which is a large portion of MMA's fanbase whether people like it or not, Fedor doesn't exist basically. It's not right, seeing as he helped build the sport and is part of what makes it great but it's the truth.