All I want to hear from you fine folks is one (or more) example(s) of “conventional wisdom” that proved not to be the case. Your favorite(s), particularly the ones you believe many people STILL believe. (Is this motivated by statistics in my Veterans Day post? You betcha.)
Example: Bra burning at the first significant feminist rally in Atlantic City. Didn’t happen. There WAS conversation about doing so, but the organizers couldn’t get a fire permit.