How long SHOULD IT TAKE for an inexperienced/ignorant/incompetent person to become experienced/knowledgeable/competent? Why?

Better ask that of his constituency.

How long before we have voters who can actually think before they pull the lever?

How long will it take for you to realize that asking questions like this one whose answers depend on such a wide variety of factors means that the potential answers cannot be locked down to simple, quantifiable terms?

What answer(s) do you expect people to give you here?  Milliseconds? One minute? Five minutes?  Three hours?  A few weeks? A decade?  A few lifetimes?

The complexity of the subject matter, times the level of intelligence of the student, divided by the teaching method, plus the aptitude of the instructor, minus the obstacles and barriers to learning . . . et cetera, et cetera, et cetera. 

it might take a long time depending on the person

Apparently, some people take a lifetime.

As RandyD points out, this is an unanswerable question. We are human beings with natural, individual brains, not programmable automata.

To learn anything new you need to want to learn it, the aptitude to learn it, plus appropriate, reliable help and sufficient time and opportunity.