Another angle is that, since society was becoming more rigid, other industries were self-censoring, and companies like DC already had their own Code-like set of guidelines, exactly what happened would have happened, plus or minus a few years.
Well, no, that's not true. At a bare minimum, no Marvel comic would have resorted to using the word "zuvembie" to get around the ban on mentioning the undead.
Or to go more extreme, the lack of a Comics Code could have driven customers (or, rather, distributors) away and crashed the industry well before 1960. Or the government might have stepped in to censor the industry outright. Remember, there were many book burnings in the '40s because of the "filth" in comics. Wertham wasn't some Bond villain cackling in his chair orchestrating some movement, he was just a symptom.