Saying that Trump won because any ONE thing is fatuous.
Did Clinton, in hindsight, run a shitty campaign? Well, duh. She ended up losing the electoral college (and the popular vote outside of California, #kermitdrinkingtea and all, but it's true). Did she not campaign in states that she took for granted and shouldn't have? You betcha.
Did Russia fuck with the election and did Comey upend the table a week and a half out? Yes and fuck yes. There are a multitude of reasons why we're where we are; anyone who tries to tell you it's just one thing is a fucking moron, or etoilet. But I repeat myself.