The Bateses of Tennessee are just behind the Duggars of Arkansas. Not even close to the 18th century Vassilyevs though.
Because they have their own minor-league spelling bee circuit. Having a qualifying spelling bee league that is, at times, tougher than the actual competition is what results in the extreme over-representation of Indian kids (1% in population, 11% in the spelling bee) at the national-level Scripps spelling bee. Where else have you seen such a phenomenon?