The lesson I'm referring to is that injuries happen... they happen early in camps, or late... before tickets are sold, and after. There are things that can be done to mitigate their effects... but assuming they won't happen is the quickest way to assure failure.
UFC 149 left fans chanting for a re-fund after injuries decimated the card, and the patchwork main card did not deliver... UFC 151 was an even worse debacle... Strikeforce went down twice in the fall, leading to the death of the organization. UFC 153 was a near miss after Koch, Aldo, and then Rampage all went down, but Anderson Silva, and Big Nog stepped up on short notice to save the show. Since October though, UFC has been on a good run. The injury bug that plagued most of 2012 had not hit the big names too hard recently. UFC had also built some better cards that looked like they could absorb injury a little better.
UFC 154 - GSP vs. Condit, with Hendricks vs. Kampmann in the co-main. Either guy from the co-main could have stepped up.
UFC on FOX had Rampage, and Pettis/Cerrone backing up a FLW title fight
UFC 156 - Aldo vs. Edgar, Overeem vs. Bigfoot, Rashad vs. Lil' Nog - Both co-main's could have stepped into the main.
UFC 157 - Ronda vs. Carmouche, Hendo vs. Machida - A lot of people said the co-main should have been the main anyway.
UFC 158 - GSP vs. Diaz, Hendricks vs. Condit, Ellenberger vs. Marquardt - This card did survive an injury one of the big fights... and was built to survive a Diaz pre-fight meltdown.
Even UFC on Fuel 8 was a stud card.
Now UFC on Fuel 9 happens. It was a card built around hometown stud, and top 5 LHW Alexander Gustafsson facing a tough test in Gregard Mousasi. The card was suppose to have a quality co-main event with Meisha Tate vs. Cat Zingano throwing down to determine the next challenger for Ronda Rousey... but UFC's VP for European Operations turned down the fight, saying the market wasn't ready for WMMA. When that happened, I think everyone expected a quality co-main event to take it's place... and then that never happened.
Compare the last two Fuel cards... UFC on Fuel 8 had Stann vs. Wandy, Hunt vs. Struve (3 fight win streak vs. 4 fight win streak), Sanchez vs. Gomi (Sanchez returns to LW to fight Gomi coming off 2 straight wins), and Okami vs. Lombard (top 10 MW's both coming off wins) ... UFC on Fuel 9 has the UFC debut of Ryan Couture vs. Ross Pearson, a potential loser leaves town fight between De Fries and Mitrione, Pickett vs. Easton in a fight of guys coming off a loss (I know Stann and Wandy were coming off loses... but don't even try to compare the star power, and fan base of Wandy to either of these BWs)...
OK if this is all they are going to give us... then at least they will put a few other LHW fighters on this card in case one of the headliners gets hurt... nope. UFC couldn't have put Davis vs. Magalhaes on this card? Throw together something like Bader vs. Vera once the Tate/Zingano fight fell through? Now what are the options on less than a weeks notice with an overseas card? Davis or Magalhaes should be in shape getting ready for their fight on April 27th... Glover might be in decent shape, but now that he is in every discussion when title contenders come up, fighting a tough SOB like Mousasi overseas six time zones away on six day notice would be a risk not worth taking. Will work visa's, and weight cuts hurt this card?
I don't know how this will all turn out... but as of Sunday evening I'd be pissed if I lived in Sweden and had a ticket to a Couture vs. Pearson main event.