Hate to say it like that but NASCAR has to compete with College Football and NFL when we get later into the season and the Chase was put in to compete with that.
NASCAR just got 33% more money from Fox to run the first thirteen races. I assume that there's not a lot of concern for attendance when they can rake in cash from TV and race sponsors. There's been a lot of talk that people today have a short attention span; they need to be able to constantly switch between football and racing.
I don't think that's true. I think they've been told that over and over to the point where they're just doing what they've been told. I think that TV broadcasts, in trying to serve the short-attention span, do more and more annoying things that subconsciously drive viewers to seek a break from them. I no longer have TV but was fortunate enough to catch an illicit transmission of the Charlotte race. I could barely keep my eyes on the cars with all the distracting tickers and banners and logos popping up on screen. They reduce the race coverage by at least 25% just to fit all that junk in. I had to keep turning away because my eyes were tired from bouncing all over the screen.
Fans who attend races in person don't get to hear all those mentions of "a can of Sunoco fuel and four Goodyear tires".The networks (and NASCAR) get paid a lot of money for all that subliminal advertising. That tactic isn't as effective for fans in the bleachers, so agencies won't pay much for the privilege.
Auto racing already has higher attendance than the NFL or any other sport. They don't care about asses in the seats. Professional sports is an advertising delivery system and that's best done on TV. NASCAR doesn't want more fans, it wants more viewers. For decades, the Indy 500 has been the world's largest sporting event. The race pulls in fewer TV viewers than the Superbowl (and maybe the Daytona 500), so the series is relegated to the last five minutes of Sportscenter.