There are so many other traits and characteristics that are necessary to maintain a democracy--not just IQ level. Lack of courage, I think, is the big one. What we've seen since January is that so many people and entities have buckled under without a fight. Law firms, corporations, and individuals. There is a lack of courage and an unwillingness to duke it out.
The personality traits and skills that enable courage are rare. They are confidence and public speaking ability, among others. Public speaking is the number one fear of Americans, so that tells you something right there.
In a way you'd have to say a certain degree of financial independence is a factor. You have to be able to say "take this job and shove it." This doesn't mean you have to be rich or well off. It could mean you have another wage-earner in the family who might support you while you land a new job.
OTOH, you'd have to be stupid to try a takeover. I've thought about what it would take and what stops me every single time is that Americans are trained to have freedom. They don't like it when their freedom is threatened and they will work against you. This means you would have to keep fighting back for at least a generation, and that's a high price to pay.
I used to work for a professor of Russian history and she told me the reason the Russians can never make a go of democracy is they've never sustained it long enough to mold a generation of people who know how to use it, to live it, to promote and protect it.