It would have forced the press onto Parler. Twitter essentially has two user bases, twitter leftists and politicos/the media/establishment. Trump would have dragged the press and other Republicans onto Parler, and with them, all the TDS suffering leftists probably would have opened accounts as well in order to dunk on Trump. That would have created enough of a critical mass that Amazon would not have yeeted Parler for fear of the backlash. As it was, it was only a group of conservatives using Parler and Amazon doesn't give a single fuck about taking down a platform that only conservatives use.