Hiring and firing is all gut. There are all kinds of mistakes in hindsight. I'm, frankly, not interested in "random example to prove a point" because all sides could play that game until the end of time. Would anyone believe me if I told you early on that a coach like Bob Stoops would win only one national title, despite a very productive 18 years? Or that Dean Smith or Tom Osborne would win any titles? You just don't know for sure, so it's a pretty pointless exercise.
The best you can do is make an educated guess on if your guy is the right one. I've never felt Riley was the guy if your goal (as was stated) is to exceed that 9 win plateau and win titles. I simply did not, and do not, feel a guy with his track record suddenly becomes that coach. Others disagree, and still others didn't even have a clue who he was (and maybe they still don't). I feel that if your goal is to exceed 9 wins (not a trivial matter) then there is some element of risk. It may take several hirings to get it right. Going from a 9 win standard to 10 sounds like nothing, but each win takes more and more ability; it gets disproportionally harder and harder.