I read a statistic that 50% of grown up Americans have only 6th grade education. Which means that what? 60%-65% may have 9th grade?
The vast majority of people is uneducated and only responds to simple thoughts: as someone said: they see their wallet shrinking, and they decide to voté for the alternative. Other more complex issues don't matter, they don't care about them.
The same thing happened in my country (Mexico) where we have also tons of uneducated people. The people voté for the sound snippet, for the demagogue who told them what they wanted to hear.
And similarly, the other parties in their smugness didn't understand why people didn't vote for more complex issues.
It's sad, but most of us (highly educated people) live in a bubble.