Irrelevant and out of touch with where music was heading? He had his own ship to steer, why would he care where everyone else was heading? Which artist can you think of with a 50 year career who hasn't experienced ebb and flow? It happened to Dylan, it happened to Newman, and it may have happened to Lennon, too. McCartney? Has he always had his pulse on "where music was heading"?
The Los Lobos/Simon story is a painful one that affected my feelings toward Simon for a long time. In time, I've learned, especially since I don't know the whole truth, to forgive him, in spite of those unfortunate incidents, and enjoy his music for the brilliance that it is.
This much is certain, it wasn't trending African Tribal and if it did I guess I missed that tsunami. He had flow and he has had ebb ever since, that's my point, he's not on the radar musically. That won't keep him from being feted for his past accomplishments but Dylan, McCartney, Lennon he is not.