Because technocrats tend to make terrible politicians. They have a tendency to be impractical idealists on their field of expertise, whose importance they greatly overestimate, and they're semantic bickerers who can never find a consensus.
And the moment you have to make a choice who gets to join and run a committee you're back to democracy again because there is no objective way to determine who the best technocrat is.
Unless we're talking about a small polis where you only have a handful of experts and you might as well let them run the show it's just not feasible.
Much more practical to let experts weigh in when their opinion is needed. Which is what's happening in modern democracies.
I got 08:59 on that test. Bloody red flyover states are all square...
Crusher, your laizzez-faire attitude to brain scans is impressive. "Neurological test thingy" ... "measured brain activity... or something"