I know how you feel. King seems to assume that his readers have got half their lives to devote just to his books alone. I would still say that J. D. Salinger's complete works - amounting to little more than 400 pages - still outweigh King's total oeuvre. His massive output would suggest that he has an awful lot to say, but I think there is reason to doubt that.
Writing his never-ending stories has doubtless been therapeutic for him but I doubt whether they are very therapeutic for his readers. Psychologically, there is no doubt that writing is more healing and cathartic than reading.
Still, every reader has the choice whether to read his books or not.