Judo is not dominated by the Japanese. They do well, but the French, Koreans, Russians, Georgians, Armenians, Germans, and many other countries consistently win medals at the Olympics. Judo has athletes enter from as many countries as wrestling or boxing, it's a very competitive international sport. People care a great deal about Judo outside of Japan. You're simply incorrect on this point by pretty much any measure.
And whether the Gracies fought any Olympic wrestlers is an odd thing to focus on. I don't know that there were too many Olympic wrestlers looking to fight in the early days of MMA, the only ones that come to mind that fought in even relatively early events (in the late 90s) were Dan Henderson, Mark Coleman, Mark Schultz, and Kevin Jackson. And they had mixed success. Coleman and Henderson went on to have very successful careers, Schultz and Jackson (the best wrestlers of the group, both Olympic gold medalists) retired with only a few fights and middling records. Incidentally, for both of them their losses were all by submission. In any case, I'm not sure which Olympic wrestler you would have liked to have seen them fight, and how you think they would have done. It probably would have been like most of their early fights: they get taken down or pull guard, and then choke or armbar the guy. It doesn't really matter how good someone is at wrestling if they don't know anything about submissions. And if you say 'well, they could have learned some submission defense and then what' I'd say you're taking the Gracies out of their era and comparing them to the beginnings of true MMA which as I originally said I don't think they'd do very well in..
