Comparing the Superbowl (Daytona 500) to a week 3 football game (Phoenix race) is not the same.
Also, the Grapefruit League spans across many different cities in FL that are few hours apart. The Cactus League is only in the Phoenix area in which the furthest two stadiums are less than an hour apart. Most of the stadiums are less than 30 minutes from each other.
"Nearly a third of spring training’s economic impact came from Arizona residents, and Arizonans bought 42 percent of the 1.9 million tickets sold,
according to a Cactus League report."
https://cronkitenews.azpbs.org/2016/02/23/cactus-league-economic-impact-valley-arizona/
42% of 1.9 million is a hell of a lot locals.
AZ Cardinals average attendance for 2016, 64,800. That's just the people that go into the game. Many people just sit in the parking lots and tailgate. And with the Cards a potential Superbowl contender, many would choose to watch football at home than go to the race.
https://www.statista.com/statistics/250072/average-home-attendance-of-the-arizona-cardinals/
Again, not saying NASCAR isn't at fault, but you have to give them a little leeway when it comes to local competition. They should move the race to April.