I somehow doubt the emails lost Hillary the election. If the disclosure of Trump's pussy-grab video couldn't lose him the election, this didn't do it for her.
What I find more interesting is what if we did obtain cast iron proof that Putin ordered attacks to sway the vote, and that they worked? Would there be any grounds at all for the election result to be challenged or is it just a case of "what's done is done"?
The impact wasn't the "breaking point", but I'd argue that this, combined with many other things (such as overlooking the three swing states everyone thought she'd win, shy Trump, large undecided voters, Comey, etc.) could be taken together. I'd agree that this wasn't the sole thing that lost her the election, but I don't think many people really know what actually did lose her the election. People have theories, all of which are colored by personal biases, etc., so realistically, it'll probably be years before anyone really knows what actually went down.
Well, if there was a video of Putin ordering the hack attacks/campaign (for example), there'd be a lot of outrage but I don't think that it would lead to a new election. Remember that the accusations center solely on getting emails from Podesta and the DNC and giving them to Wikileaks to discredit Hillary. This wasn't vote rigging, so it'd be a bit tough to make an argument for election fraud. There are arguments that could be made, but I'd be doubtful of how much it'd hold up in a court.
The main point of all this is to point out how much of a Putin puppet Trump is.