When the Democrats decided they wanted to be the "Urban Elite Party" and paint the Republican party as the "Rural Uneducated Party", they basically threw away Iowa. Iowa is as middle class plain-folk as you can get, so they will naturally align in opposition to the Urban Elite. That was a tactical error in how the Democratic Party formed its identity.
100 percent spot on. It's also a huge part of how they lost such a ridiculous chunk of blue collar workers in spite of labor leadership being solidly Democrat for decades.
Poor whites and rural hicks became the only working-class people it was still socially acceptable to openly mock in public. This was noticed and exploited by the right with dire consequences for our current political landscape.
Of course, a ton of other variables were at play as well, but the certainty that so-called "coastal elites" held them and everything they valued in contempt played a huge role in convincing blue-collar and middle-class rural whites to vote against their economic interests.