For example, as mayor of NYC, Bloomberg governs about three times as many people as Bill Clinton did as governor of Arkansas.
No, NYC is not a cross section of the US, but neither is Arkansas, and of the two, I'd say NYC gets closer to more of the population.
Absolute number of people is not the determining factor in any of this, but with no major cities in Arkansas, I reject the notion that Bill Clinton's governorship gave him experience with urban issues.