In my experience, the discrepancy between tier list and tournament placing is due to individual players. A tier list based on match ups just provides a laundry list of situations that can be beneficial/detrimental to two sets of characters. However, these characters are controlled by players which have a big effect on the outcome of the match.
One of my major weakness when I started playing fighting games competitively is something I liked to call "situational freeze". This is when you get in your head that character X will do this if my character Y does that. Most of that information comes from match up chart and in game experience and happens when you play against the "character". Problem with that sort of thinking is that you start to think of everything your opponent can do, and put yourself in a situation where you think you cannot do anything without being punished hence you don't do anything but try to react and because you don't press an offense, you wind up in a defense posture trying to avoid mix up city, hence "situational freeze".
When you play against the player and not the character you learn what your opponent can and cannot do, for example DJT putting Chris G in rocket string during evo. A player who plays the character would not attempt that set up because they know the Match up chart says it not advantageous, but when you are playing the player, what you are trying to do is win by finding out what they specifically don't know about the match up. No one is all knowing and this is why tier charts and tournament placings don't match up.
