I'm not saying they can't do a good number now & then, they can (and have).
I'm saying they blew a chance to make millions of new fans that night. That was the most important night in MMA history since Griffin/Bonnar. Griffin/Bonnar won people over and sparked a boom. Cain/JDS drove people away and kept them on the same level when that night could have sparked another boom and took them to a next level. Joe Sports Fan doesn't care about UFC, and i'm willing to bet 3 or 4 million people watched that night that haven't seen a fight since.
If you want a small sample size, check the chatbox on this site on and UFC fight night. The usual suspects (Kuzzy, Empire, me, Shogun etc) talking fights. The night of Cain/JDS, EVERYBODY was talking UFC, they had non fans watching, and it turned into a running joke. A lot of uninformed people thought it was fixed because the KO was so weak. That's a killer. Show those people Bendo/Guida, you have water cooler buzz.