Trump's hubris is no longer a refreshing crudeness that most of us laughed at. It is rude, embarrassing and off putting. No one wants to see a man treat a woman the way he did at the debate. We teach our children to be gentlemen and considerate, so having the leader of the free world be a male chauvinist pig would set us back in ways we have not considered.
Trump's hubris represents the kind of over-the-top confidence that many Americans do not like. Americans value humble attitudes that make their leaders seem more like their equals. Trump's wealth and arrogant attitude set him apart from the average American making them less likely to vote for him. Also, hubris can possibly make Trump less likely to notice his own mistakes. If he is unaware of the areas in which his campaign needs improvement, he will fail to make it better to win over more voters.
Donald Trump is not fit to serve as POTUS. He has no experience in government, he has a terrible personality, and does nothing but belittle and bully people that don't follow him. He has shown racism, bigotry, and misogyny, to name just a few of his flaws. There is no way the miserable fool will get elected.
Hubris is defined as "excessive pride." This is certainly something that Trump has. Yet it's also said that "pride goeth before a fall." Given the amount of pride that Trump has, his fall will be spectacular. It means that Trump can't expect to win the election if he's so absorbed in himself that he can't stop to think about his own supporters.