Sometimes judoka do beat wrestlers. It's just that a fast shot and fast scrambling is hard to beat.
A better sample size for judo vs wrestling would be to look at M1 Global, as M1 seems to cater to a better balance of both judo and wrestling strong countries. The histories & participation there are much more even than UFC where bjj and folk-wrestling are stronger. Still tho, like above, the distance shot and scrambling of folk is hard to beat.
Also, Shields was not the best wrestler that Akiyama fought. Aki fought 2 Olympians (one a silver medalist) before UFC.
Maybe due to lack any decently organized judo for mma concept, it seems many judoka suffer an identity crisis in mma. They don't know if they are wrestlers or bjjers. Aki looks wrestler, but Takimoto or Bu Kyung Jung (both oly medalists) for instance, while incredible throwers, would often seem to prefer fighting from their backs.