So, my point is that measuring democracy ("power to the people") against the purposes of aristocracy ("power to the best ones") is pretty misguided...
I'd say measuring the ideal instead of the reality isn't all that useful.
Think about it as voting for the dinner choices. It is not about finding the best chef, it is about getting Spaghetti Bolognese, because that is what you feel like tonight.
For example, a vast majority of the people might share the wish to select a leader best equipped to improve the countries economic prospects.
If that is what the overwhelming majority wants, but the system doesn't enable that outcome, then I think you can argue that self-determination hasn't been expressed.
If the system in aggregate produces candidates who can't execute what the people want, but yet each individual determines their own choice of vote amongst the poor choices, can this really be said to be self-determination?