I don't think the issue is that elected officials are dumb. I think it's the opposite, most are quite intelligent. It's more that they are evil/corrupt/self-serving, and acting dumb is part of how they get away with it.
And US used to have them too. The basic approach was that if you have land, you have a stake in the future of the republic. It was debated as to whether landless would have the same stake.
I'm pretty sure I want credentialing requirements for anyone running for any public office. I'd settle for automatic exclusion of anyone displaying narcissistic, psychopathic, or sociopathic tendencies and inclusion of rational pragmatists.
I would also "settle" for picking the people I like.
Also, pretty sure that you have to be at least somewhat narcissistic to think that you should be president, and somewhat sociopathic to actually succeed.