Well anything is possible. Kentucky could have beaten Wisconsin if a shot clock violation took away points from Wisconsin, they could have beaten Duke for sure with the Cousins/Wall team. I can say anything but that doesn't matter either.
The Wisconsin reference is a good one.
In sports, especially in a single game winner scenario, there is rarely a "this team WILL win". It is all about probabilities.
In 2015, Winconsin was a very good team, and a tough matchup for us. But if we played that game 100 times, I think we win at least 60, maybe 70 of them.
Likewise in 2012, UNC had a very good team, we need a Davis block at the buzzer to win in Rupp in December vs UNC. Clearly having Marshall would have helped their chances. Without Marshall, their chances of winning that game were 10-15%. With a healthy Marshall, I think those chances go up to 35-45%, still the underdog but much closer.
Regardless, injuries, and dealing with them, is a part of sports. Most successful teams have been on both sides of the injury bug helping/hurting them win a championship, most recently for UK (97 Derek Anderson, 03 Bogans, 15 Poythress). Probably the 12 Marshall injury helped our chances, but we still would have been the favorite w/out the injury. There are always other factors too, an opponent player having the game of his life, schedule difficulty or lack of (just look at the 10 Duke opponents), unbalanced officiating (17 UK-UNC, 15 UK-Wisc), & others.