The realization that many people are not actually smart enough to figure their own interests [...]
People do what is in their own interest by definition. That's the only way you can be sure what their interest is. I think what you're complaining about is people not doing what you believe you would do in their position.
> People do what is in their own interest by definition.
No, people do what they believe at that point in time is in their interest, and may (and often do) revise and reverse their beliefs a moment later.
May acts, like voting, are by virtue of being done every e.g. 4 years, are supposed to reflect long term interest.
An analogy: Your immediate interest might be to get the gratification from eating a jelly doughnut, though your long term interest might be to lose weight and be more fit and healthy.
I'm referring to the many people who vote once every 4 years to eat a doughnut every single day of the next 4 years. There are a lot of them, and they are voting against their (long term) interests.
People do what is in their own interest by definition. That's the only way you can be sure what their interest is. I think what you're complaining about is people not doing what you believe you would do in their position.