"Scoocr, football, NBA would drool to get 100,000 rabid fans in every sunday."
You're joking, right? That's 100,000 people going to the one and only race on Sunday. Add up all of the people who go to NFL games on any given weekend and NASCAR becomes an insignificant speck.
If, hypothetically, you could run full-field events at multiple places at the same time, I'd bet you could sell out multiple NASCAR venues. Daytona, Bristol, Richmond, Indy, spring to mind. If you get a ticket to any of those places - you go. Period.
It's a moot argument because one of the cool things about NASCAR is that the whole league is on the field at the same time.