Obama sold himself on 'Hope' and 'Change' rather than specific policy and experience. That's similar to what Trump is doing, and after eight years of a Democrat in office - whom Republicans think is very liberal - its no surprise that Republicans want change. They don't like the path the country is taking for a number of reasons, many of which they are directly responsible for (economy, foreign involvement, etc.).
The problem with Republicans is they have sold their original base short by focusing too much on social issues. The wealthy rich male wasn't a large enough population once the USA economy consolidated into the 1%, and so now the Republican party has to win over the Bible Belt with pro-life, anti-foreigner (and Muslim) and gun control policies. Problem is, for much of the western half of the USA those messages ring hollow because its a far more liberal region.
Trump sucks and I told my GF"s parents that to their face....who then turned around to inform me that they support him. Good to know where they stand so we can never talk politics again.