Musically, I think Kanye has one classic album left in him, but the days of back-to-back classics have long been over. He peaked creatively in the early 2010s, and he experienced his peak music popularity in the late 2000's.
It is what it is, though. Most iconic artists reach the point where they're past their prime, if they don't, it's usually because they died really young. People bring up Prince and MJ, and they're right. Both guys stopped having a stranglehold on pop music by the mid-late 90's, and in Prince's case, dropped alot of arguably mid albums in their later years.