WI Britain and France had better intelligence about the potential weakness of the Nazi forces in 1938, and had supported Czechoslovakia. Assume the little Entente- Romania and Yugoslavia plays ball and Poland is either allied or neutral in ways helpful to the Czechs,
It is distinctly possible that the Nazis would be fought to a standstill.
The military might get rid of Schickelgruber.
How many people would be all that interested in those events 70 years later?