What lead to the decline of Dadaism in Zurich and Germany in the 1920s?
Dadaism, in a way, lead into Surrealism, but that is not to say that Surrealism is an evolved form of Dada. Wondering if there was a specific cause ofr its decline or if it was a natural sort of death for the movement.
Given that the major impetus behind the growth of the movement was horror and disgust at the conduct of the war, the end of the war basically put an end to the movement in that many of its members returned to their native countries and the atmosphere in Zurich itself soon changed to one that was less focused on the absurd horrors of trench warfare and mass murder that was occurring during the war.
There is mention of Neo-Dada activity in Paris as late as 1921, thanks to a gathering of Dada-ists there long after the war's end, but this was also short lived.
Perhaps it was increasing focus on recovery or simply the lack of that horrifying conflict that led to people concentrating on other things and moving away from the Dadaist ideals.