Then it should be an objective test. Familiarity with current events, geography, physics, calculus, micro and macro economics. Final exam of 101 courses would be sufficient. 80% or higher and you get to take office, otherwise the next highest voted politician gets a shot at it.
A board of representatives from the 10 largest public colleges gets to write, administer and grade the test.
Not to mention needing capital for the land, equipment, seeds, fertilizer, pesticides, fuel, power, storage, transportation and uncountable other misc with a price tag. Starting with trained doctors and on to even more narrow specialists.