Iowa has a general lack of geographic political polarization compared to most states, and one underrated possibility could be because it's the first primary state, it tends to get a disproportionate amount of attention, and Democrats actually work to get votes from these smaller towns and even rural communities in the state they would otherwise completely neglect. Iowa has quite high turnout in General Elections, especially once you factor in educational attainment.
It's also worth noting that Republicans do relatively well in a city like Des Moines despite it's size, educational attainment, and culture, and I think that could also be for the reason stated above.
And what's the second primary state? New Hampshire. Once again there you see far less extreme political geography than neighboring states and a very high turnout state.
Educational achievement can be quantified in many ways. IA may not have a high college rate (though thats also deceiving since many Iowans leave IA after going to college). But IA, like many of its neighbors, has one of the nation's highest school graduation and literacy rates (and with fairly good K-12 schools). Traditionally, IA and MN swapped 1-2 in these 2 metrics, though they dont consistently do that in recent years. It doesnt fit the narrative that polls try to quantify, but a farming family with children who have gotten degrees and left the state does not vote the same way as a multi-generation blue-collar family.
I do agree with you about the attention it gets though.
