>>Counterfactual history, also sometimes referred to as virtual history, is a form of historiography that attempts to answer "what if" questions known as counterfactuals. It seeks to explore history and historical incidents by means of extrapolating a timeline in which certain key historical events did not happen or had an outcome which was different from that which did in fact occur.<<
So a counterfactual historian could ask the question: "What would have happened to Germany, Europe and the rest of the world if Hitler hadn't been born?"
Let us apply this method to music history!
We could have a lot of fun with this...