The UFC's final PPV of 2014 turned out to be one of their better selling cards in an otherwise down year at the box office. Per MMA Fighting's Dave Meltzer, UFC 181: Hendricks vs. Lawler 2 drew an estimated 375,000-400,000 buys, which is up from the 310,000 for the first Hendricks vs. Lawler fight in March, and also the promotion's best selling PPV since UFC 175: Weidman vs. Machida in July.
This, more than anything else, could be what caused the UFC to withhold Rory MacDonald's title shot and likely make way for the rubber match, possibly for the Memorial Day weekend show. It looks like, albeit with help of a strong co-main event of Pettis vs. Melendez, the UFC brass see some traction in this rivalry and want to capitalize on it before moving on to other challengers. Whether or not it's the right call is completely subjective, but you can understand why Lawler vs. Hendricks 3 could be deemed more appealing than Lawler vs. MacDonald 2.
Catching up with some other PPVs over the summer and fall, Meltzer also reported the estimated buys (in his subscription-only Wrestling Observer newsletter) for UFC 178 through 180:
UFC 178: Johnson vs. Cariaso (Main card notables: Cerrone vs. Alvarez, McGregor vs. Poirier) - 205,000 buys
UFC 179: Aldo vs. Mendes 2 (Main card notables: Teixeira vs. Davis) - Between 160,000-200,000 buys
UFC 180: Hunt vs. Werdum (Main card notables: Gastelum vs. Ellenberger, Bermudez vs. Lamas) - Between 185,000-200,000 buys
Obviously two of these cards were hit hard with main event cancellations (Jones vs. Cormier and Velasquez vs. Werdum), and the buyrates clearly reflect that. You can almost certainly attribute UFC 178 even getting above 200k buys to the strong main card and not Demetrious Johnson versus Chris Cariaso.
It'll be interesting to see if the first three PPVs of 2015 - Which feature Jones vs. Cormier, Anderson Silva vs. Nick Diaz, Weidman vs. Belfort, and Rousey vs. Zingano can give the UFC a much-needed boost after an injury-riddled 2014.