I essentially agree with you and to flippantly dismiss one of the most erudite multi-volume studies ever undertaken with a few glib one-liners isn't worthy of reply. Toynbee's "A Study of History" is universally recognized as a landmark in historiography. As the late Crane Brinton of Harvard put it, " Mr. Toynbee's study belongs ...with such works as those of ...St.Augustine, Vico, Buckle, and Spengler. It is philosophy of history, metaphysics, even theology, not narrative history."
Ironically, Arnold Toynbee's granddaughter is the British Labour Party hack Polly Toynbee, who is a regular columnist the the UK Guardian. It is probably a common trait that many of the children and grandchildren of the culturally very conservative and pessimistic types are flaming leftists. Most of the leftist writers have very distinguished father or ancestors in aristocracy or colonial civil servants.