It depends on the advertisements and the brand fame. Hyundai is still unknown in most U.S. households because it is a South Korean brand, and few laypersons know where is South Korea or the capital's name (although a "Miss Universe" contest was held there). North Korea gets more news coverage!
Here in Puerto Rico, I see many Hyundai and Kia ads on TV, radio and in the press. I also see many Hyundai and Kia models on our local roads, too. That brand is displacing Toyota, Honda, Mazda, Nissan, and Mitsubishi as the best foreign brand for the lowest cost and is now the second best selling brand locally. If the Ioniq is offered here in hybrid and plug-in versions, they will displace the Prius as the most selling hybrid. Maybe the EV model can sell well, too.
So if the Hyundai Ioniq needs to sell better, the brand has to increase their presence and even compete head-to-head with Toyota.
"Puerto Rico is an unincorporated state of the United States, and as such new car registrations data is not accounted for in the U.S. updates. Toyota follows the market at +6% to 26.4% share, exactly double the #2 carmaker,
Hyundai surging 25% to 13.2%. Kia (+2%), Nissan (+11%), Chrysler (+9%) and Ford (-6%) complete a
Top 6 unchanged on 2015. Honda (+10%), Maserati(+58%), Volvo (+127%) and Jaguar (+174%) post the biggest year-on-year gains in the rest of the ranking wheres Scion (-12%), Fiat (-19%), General Motors (-22%), Mazda (-23%), Volkswagen (-27%) and Smart (-37%) suffer."
http://focus2move.com/in-2014-the-car-market-in-puerto-rico-fell-in-double-digit/
http://caribbeanbusiness.com/strong-fleet-purchases-help-auto-sales/
So you may not see any Hyundai Ioniq sales yet, but the brand is taking off.