Ya, Azen and Lee hardly come over to our boards, partially because people tend to ignore their advice (or any pro's advice, for that matter). It takes a lot of patience and articulate debating to get the good points across for a MU, and often people who know the MU in and out will get disgusted at discussing because people will completely ignore/theorycraft their advice to the bone, and it often is ridiculous how they go about a MU discussion. It's clear that MU discussion =/= actual outcome, especially with characters that rely on novelty. It's funny how many people will come around to using unviable tools in a high level discussion like that, it's why I frankly have not liked expressing my opinion in my character's MU board often. Tactical discussion >>>>>>>> MU discussion, imo, unless you're like MK or something.
Edit: basically adding on to what Viper said, there's characters that are pretty icky that people will still play (take Xyro for example).
And no, Lucario stopped awhile ago, it's basically been a friendly chat with Thrilla lol ^_^