we have been running Tomb of Annihilation and I keep wondering why Elminster isn’t in it. The soul monger sure seems like something he would look into and a crazy multidimensional lich would probably have a rapport with the old rogue. Heh. Elminster is SO busy, with fingers in so many pies (thanks to Mystra and his centuries of building real-life friendships and obligations), that even he can't be everywhere at once.
Which, as Storm has commented darkly, more than once, "Is a GOOD thing."

— Ed Greenwood (@TheEdVerse) September 15, 2018