Do you even know your Beatles chronology? It is all relatve. The two late '60's albums you citewere very good. But vs. say Sgt. Peppers, or Rubber Soul? Apparently you do not know much about the Beatles, or have strange tastes.
Abbey Road was recorded after Let it Be. I have always thought that Pepper was overrated and prefer the two albums I mentioned.
In terms of an individual or group releasing 3 consecutive GREAT albums, one would hard pressed to find a greater trilogy than
-Rubber Soul
-Revolver
-Sgt Pepper