We live in the Heart of NASCAR world, little over an hr. from Charlotte. There never has been a large number of fans around here that fly/flew flags of their favorite racers. Around here you have license plates, decals on cars,truck windows to show that. A flag is flown seasonally whereas decals and plates are much more a permanent fixture to show allegiance.
The base has not grown smaller, in fact some of the local colleges have opened up courses for the people of color to get involved and they have kids enrolled in those classes.
The sport did not die with Dale, he's still remembered and revered, or reviled by some, but his face has been transposed to the younger guys Lagano, Stenhouse...etc. You guys have 1 race and it's the opener,and it's major but IMO FLA isn't the bell weather for NASCAR ...NC is the birthplace and it's doing fine.