People choose not to vote for different reasons. This time, a common one seems to have been a dislike for both options and desire not to have to choose a "lesser evil."
During the race it seemed every liberal/Democrat felt compelled to append their denunciation of Trump with misgivings about Clinton. Like they needed a sophisticated position despite the no-brainer. If true, then the problem isn't stupidity - it's over-thinking and second-guessing. I believe internet media encourages this, because activity requires there be something to add. We can't simply form a basic position and quit thinking about it. By "we" I mean the demographics most susceptible to thought.
I remember dinnertable politics before the internet. My family always supported a particular party, and there just wasn't much information and intrigue between elections to complicate the matter.
Considering that voting isn't mandatory in the US, they were smart enough to go voting.
Smart like the turkey. That's different than intelligence. A smart turkey does not second-guess itself.
I blamed internet media, and I suggest there also is the solution. Right now computers are doing to us more the opposite of their original purpose. Take for illustration an early mechanical "computer" for calculating artillery settings. Its job was to process a lot of variables like wind speed, shell type, even air pressure, and provide us users with a simple position to set the gun. In this metaphor the gunner is the voter. Now what computers do for voters is rather confuse our basic intentions by outputting variables at us, for us users to puzzle over. It keeps updating the gunner of every little wind change, so the overwhelmed & indecisive gunner fails to fire. I want to turn this situation back around, so that computers process the mess of changing variables and provide a simple output, while we focus on our basic intent.
Some form of app. Like a hybrid "political compass" to lock a voter's basic intent, with an information filter like an ad-filter that processes information into simpler output relevant to the user's political beliefs. I think Google could devise a totally impartial algorithm. At the least it would remind us users where we stand politically, lest we get lost in the details.