Trump is the Great Disruptor. He is doing the Repub Party a great favor by going to where the votes are - the ordinary people of America like me. The wealthy will always be mostly Dems, as will (for no good reasons) the minorities and the effete snobs. But there are lots of other people in America, and they have felt voiceless in DC.
From I was wrong: Trump WILL be the next president:
Winning an election is still very much about connecting personally with key voters and you can only do that if you present a clear personality or brand to the voters in the first place. If you're the person who sees Trump's personality/brand and have decided you hate everything about it, I have news for you: You're not the target audience. But you're still proof that Trump's messaging is at least very clear and that's often more than half the battle in business and politics.
Related, from Reynold's Donald Trump is the response to a bullying culture:
...when “respectable” people won’t talk about things that a lot of voters care about, the less-respectable will eventually rise to meet the need. That’s what Trump’s doing. And a lot of people are cheering him on not so much because they’re fans of Trump personally as because they’re happy to see someone finally stand up to the PC bullies.