There is little incentive for the ISU to do this.
The ISU derives its power from the federations and the IOC / ISU partnership. Its "big brother the IOC" may very well have made it clear that it was in the ISU's interest to favor a certain outcome.
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Now, most will remember there was a famous cheating scandal in 2002. You would think the sanctioning body would have taken steps to clamp down on cheaters and clean up the sport. In fact the ISU did the exact opposite -- the ISU did everything in its power to make cheating harder to discover and thereby likely to continue if not increase. Additionally, everyone saw the reaction by Cinquanta and the ISU after the controversy erupted. They don't care. Conflicts of interest? They don't care. Whether cheating happens or not, they don't even care what the mere perception is. They simply do not care, and that's why they have the audacity to do what they did at Sochi ... because they realize after all of these years, the figure skating community as a whole would lie down and take it like the passive and indifferent people they are. Is everyone like that? No. But on the whole? Seems like it to me. The competition was so blatantly rigged, but meh, let's all hug afterwards and move on to the next one! That seems to be the general sentiment.
We've already gone over the evidence so many times in so many threads. The tech callers called everything wrong. The step sequences were incorrectly called for Sotnikova and her competitors, giving her an advantage. Maybe a mistake? OK ... well they also did not call any of her downgrades. Then the judges suddenly took her from 7s to 9s in PCS overnight. Then she received GOEs that were unheard of. Then you start to notice that the ISU "just happened" to assign two out of three ethnic Russians on the tech panel, with the power to conspire together and call the tech calls inaccurately. Then you start to notice someone like Alla who curiously attended every one of Sotnikova's events on the season, despite her conflicts of interest, even though more than a dozen other qualified Russian judges were available. And then you notice people like Balkov on the judging panel, who have been convicted for cheating in the past. And then you notice that Didier Gailhaguet, a convicted cheat, is widely believed to be the next in line for ISU president. And then you just keep noticing things like that.
It did not matter what any of the other skaters did. Yuna was not "flat", and even if you weren't enamored with her performance, she could have received the same TES score she did last year at Worlds, which is widely considered one of the best skates ever, plus the Olympic boost in PCS score .. and she still would have lost the competition by a few tenths of a point, as I showed above. She could have done 8 triples and she still would have lost. She could have skated so well that everyone in the arena started floating in the air, and she still would have lost.
The reason is because the competition was rigged.