MA cannot be considered out of date yet because nothing has come along to surpass it.
I believe that is one of, if not the main reason why Jim does not feel the need to work on it or anything else at the moment. He has said before
in this thread "from a money standpoint, I don't actually HAVE to do any more work on the Aquarium, or anything else" Jim is living comfortably and MA is still the measure of the best in its class for 5 years now. No worries, hence, no need to move forward at the moment.
Though, in that same thread, Jim has let slip his fear of failure and need for approval. Perhaps these are also holding him back a bit.
Then, I'm sure many of you here remember his bout with artists block a while back. I wonder if he has really ever gotten over it.