I don't think so. Many of these tracks were around before TV. Also, how would this explain the popularity of local short tracks, and auto racing being the NUMBER ONE spectator sport in the world? Fan interest in auto racing happened long before NBC missed almost every restart for commercial purposes.
Sure, NASCAR was popular in the south, but TV was the biggest reason it increased its audience to what it is today. Aggressive marketing was also another. That is why there are tracks all around the country now.