The NFL's dip this season is notable, and it will be interesting to see how that situation develops. It is also important to understand the context that NFL ratings have been rising year after year for more than a decade, to record highs just last year. NASCAR ratings have been decreasing year after year for a decade, with an accelerating decline the past three years.
With the NFL, the primetime showcase games seem to be suffering the most. Viewership for Sunday afternoon games, which are the highest rated games, are trending back toward even or up. The people really digging into the numbers are discovering that about the same number of people are watching the NFL, but spending somewhat less time doing so. I wish that were true of NASCAR, but more often than not, it isn't.