You're almost making it sound like the Gracies rigged it. It was a legit tournament.
Early UFC's were about pitting different styles against each other to see which one was the best and which are mostly BS. Yes, the UFC was partly ran by Rorion Gracie, but the Gracies stood the same chances of losing to the other style(s) of MA just the same. If any other styles dominated like Gracies did, of course they were going to make the big $$$ and boast their style for worldwide recognition, just like the Gracie did with their BJJ.
Royce Gracie fought many who were his size also, and not just bigger fighters. Come to think of it, most were around his size and slightly bigger in the quarter finals. But isn't it pretty damn impressive to chose to fight someone much bigger and take such high risks to prove the point that BJJ is supreme? They chose Royce because he was small and wiry. Rickson was the real beast of Helio's lineage. For the Gracies to pick the smaller and weaker, Royce to represent them with such risks just to make a point, well I think they deserve all of that glory and more for their style.