Look at the data, she had a clear lead that deteriorated as soon as the (unnecessary and unprecedented) Comey letter was released. I love how all the head lines leave out the fact that she admits that she and her team made a ton of mistakes
I read a lot of threads here at the time, and IIRC the substantial lead she had after the third debate was starting to evaporate a couple of days
before the Comey letter. It's a detail that is often overlooked, and in the whiplash of that election season and everything that's followed, I hadn't given much thought as to why.
My best guess is that Trump stayed reasonably well behaved down the home stretch, sticking to the tele-prompter, and that people have short memories. So, I suppose it's possible that she may have lost the electoral college anyway.
With that said, however, when an election result is that close, after so many twists and turns, it's hard to discount the importance of the Comey letter since it was the last twist and it occurred with not much time left. Late deciders broke heavily for Trump, it may have caused would-be Hillary voters to stay home, and there was also a week before its retraction that voters may have thought there was something to it -- a week during which there was early voting in Florida.
