It's not actually true that no-one remembered the easily hackable voting machines were there. Trump dredged it up and made a lot of noise about it, so naturally all the good Resistance folks on social media insisted that this was a Trumpian lie and it was actually impossible. Wired even ran an article claiming it would require some ludicrously absurd conspiracy to rig the election: https://www.wired.com/2016/10/wireds-totally-legit-guide-rig... Like, this wasn't just ignored, people were actively fighting against the idea that it was true for partisan reasons.

This only changed once Trump won.