Justified or not, Nancy Pelosi has been a lightning rod for Republican criticism. Replacing too many GOP House members with Democrats, so the argument goes, would make the hated Pelosi majority leader. The ability to articulate this argument makes Pelosi a liability going into the 2018 midterms. Replacing her as House minority leader before November would take a much-used rhetorical arrow out of the Republican quiver and would deprive Republicans of sufficient time to adequately demonize her successor.
Will House Democrats take this step to increase their prospects in November? Likely not.