The thought is that there should be small, rural communities, without ant high-tech, so that the masses wouldn't rule large states, because there would be no such thing as a lagre state without electricity, modern communications, etc.
I doubt it'd last all too long; larger states have formed under old-school undemocratic rule countless times before modern times, and sooner or later, it'd happen again, and the masses would be robbed of their power. Unless something by force would manage to keep it otherwise.
Before then, though, you'd have half-arsed mob rule on a smaller scale. As the new culture develop and knowledge recess, I'd expect widespread superstition - and all the nice things that come with it - to make a grand return.
And unless you'd somehow prevent technological advancement from reoccuring in the long term, humanity would sooner or later find its way back to its current path.
Humanity, by its nature, is like a ticking bomb that way.
The problem with a meritocracy is the merits that allow you to climb aren't the merits that would allow you to govern well....
Depends on how the system is formed; if individuals simply grab power according to the raw ability to do so that they've gained, it'd end up a bloody mess. If the power is distributed by the above levels of the system according to evaluated merits, though, you could get around the issue. To implement it, the very top of the government would have to be autocratic.