I'm not saying she was a bad candidate. She probably would have won even in a more open field with proportional coverage. But the appearance of 2016 being her victory lap really soured a lot of people. But maybe if there was a better push for someone like O'Malley and she had a real 3 or 4 dog race, she would have been seen as having to fight for it one more time. And maybe that would have driven her to do actual leg work in the rust belt states (Sanders did win Indiana, Michigan and Wisconsin which should have tipped her team off to something).
And while it is unfair to hold it against her, you can't ignore 30 years of GOP attacks. They knew that was going to wear people down going in. the perception of her being handed the party's nomination didn't help.
Trump didn't win because he inspired more voters. Hillary lost because fewer people were inspired to come out. OH, WI, MI, IA, and NC all had significantly lower percentage of turnout since 2012. That is 5 states that went from Obama to Trump. 75 electoral votes.