I've worked for years with several hardcore NASCAR fans.
Listening to these guys who grew up loving the sport, there are 3 things that have led to the fall in popularity, IMO.
1. The death of Dale Earnhardt. This can't be overstated. Earnhardt fans rank right up there with BBN as far as devotion to
their guy. When he died, many hardcore fans lost interest.
2. Taking races out of the South and away from traditional tracks like Rockingham and Darlington.
3. Toyota entering NASCAR and the demise of Pontiac. Right or wrong, the Toyota thing was a huge deal to the hardcore
fans. They absolutely hated it.
I remember years ago, you could always tell there was a race at Bristol. There would be miles of RVs and campers coming through Bell County on their way to Bristol.
Nowadays, nothing.
I agree with the OP, NASCAR is dying.
I live near Bristol. While the August race is still fairly popular, it's nothing like it used to be and they may as well do away with the spring race. In past years when it was race week, you didn't bother to go out to eat because the restaurants would be packed. Now, you wouldn't even know the race was here if it weren't for the local news coverage.
With sponsorships (Monster's sponsorship is reportedly about half of what Sprint was), ratings and attendance dropping, it will be interesting to see what happens when the lucrative television contract expires in 2024. At the rate it's going, NASCAR may find itself loading up in the garage area and hoping they can make the next race.