Ask yourself this. When the past government of America headed by King George was removed just how civil were we? The Boston Tea Party? Well, that was rather rude as was the UnCivil War. The French weren't very civil to Louis either.
Civility comes to an end and calling for it isn't effective. What would be is to address the issues in an effective way before civility fails.
Way back when there was discussion as to whether the possibility of removal of a President by impeachment. Ben Franklin was arguably the one who laid it out in a way that it was understood what it had to be. The fear of incivility was hardly a concern, they were all baptized in blood. No, impeachment was the option to the only other means available to the citizen -and these are Franklin's words, not mine - assassination. What was the threshold for removal? No not the claimed in ignorance requirement of criminal activity, but by being "obnoxious", and in the context of the day we've already passed that.
No, civility isn't the issue, it's the lack of aggressive but legal correction of issues we face. Civility would not be a preventative, merely a casualty in a progression of history repeated again and again. Ben Franklin and the others would have told you that things can very much get worse.