In the Northeast US, if you ask someone if they are a race fan, they might ask which horse you like at the local track. For many auto racing doesn't even exist. A quote from Jayskis, that follows NASCAR
"It was difficult to look at 200,000 fans packed into Daytona Speedway and not imagine that auto racing has become one of America's favorite sports. According to a recent Gallup poll, however, auto racing isn't very close. The pollsters asked Americans to name their favorite sport. Football was the easy winner with more than 43% of the voting. Basketball was second with 12% and baseball followed with 11%. Auto racing landed fourth with just 4%. The poll results didn't mean that only 4% of Americans follow auto racing, only that 4% found it to be their favorite sport"
Open wheel in any form is less than a blip.