If they didn't, it would be carnage. Everyone thought the Republican party was in chaos. It is. No one realized how bad the Democratic party was as well. They pushed an unpopular candidate, and yes, the well was poisoned for her from the get-go, but she also isn't interesting. Donald Trump engaged with enough voters in the right states to win. The Russians helped with the fake news stories, and conservatives lapped up the fake news because they wanted to believe it. It used to be that a lie could make it halfway 'round the world before the truth could get its pants on in the morning, but now it can make it around the world twice, beat up the truth, and take its lunch money.
Democrats have to appeal to more than just city dwellers. Republicans have convinced poor rural areas to vote against their own self-interests by appealing to religion and folksy charm. Donald Trump also made them believe he is some sort of financial/business guru, when he isn't. Democrats did a terrible job of repudiating Trump. Republicans did a terrible job of repudiating Trump. Now they're here. Now they're staring down the barrel of 4 years of an unstable, bigoted, conflict-of-interest machine who is literally an Internet troll, as their president. Hey, maybe instability works in business, but something tells me you want a steady hand at the wheel of government. If I thought Trump was mostly an act, that would make me feel better. I don't have any reason to believe that. He's been doing this for too long.