Here in Boston, our blood pressure is still racing over the unbelievable result of last night’s Super Bowl. The odds of a 25-point comeback with just over a quarter to play are incalculably long. But Patriots fans aren’t the only ones rejoicing this morning; no doubt there’s also euphoria at the NFL’s offices as last night’s game proved once again how riveting professional football can be.

However, the exhilarating Super Bowl cannot fully mask the fact that from a TV audience perspective, this was a season the NFL would just as soon forget. Last Friday MoffettNathanson shared their tally of the final numbers: compared to 2015, overall regular season 2016 TV viewership was down 9% and first 3 weeks of post-season was down 6%. Monday night football was down 13%, Sunday night down 11% and Thursday night down 9%. Compared to 2014, overall regular season was down 7% and ESPN Monday night football was down 15%.

Early in the season, as the shrinking audience storyline began emerging, a lot of the blame was put viewers’ shift in focus to presidential politics. That theory was borne out, to some extent, as MoffettNathanson noted that post-election audience erosion improved from minus 12% to minus 5%. But the decline is more far-reaching and MoffettNathanson rightly points to the absence of several marquee players, poor match-ups, too many ads and the unfair comparison vs. a strong 2015 audience driven by heavy fantasy promotions.

In the offseason the NFL will no doubt be trying to address all of these issues, to the best extent they can. But the biggest challenge seems well outside of the NFL’s ability to control: the increasing number of choices viewers have for how to spend their time, other than watching an NFL game. At the top of the list are watching online video (especially binge-viewing ad-free programs on SVOD services), engaging with social media and/or playing games. All of this is compounded by the widespread and instant availability of scores, which reduces the need to actually watch football.

To be fair, I’ve yet to see research that quantifies the impact of these 3 factors, though I have no doubt these will be coming. The factor that is most intriguing to me is online video viewing. My hunch is that the broad adoption of SVOD over just the past 3 years is starting to impact casual fans’ affinity for watching football. Remember, Netflix ended 2016 with 49.4 million subscribers in the U.S. alone, up 48% vs. the 33.4 million subscribers it had at the end of 2013. Three years ago, Amazon had yet to really ramp up its originals. Then there are all the other great sources of online video today. Last but not least, connected TV devices have exploded in the past 3 years and are now in two-thirds to three-quarters of all broadband homes, putting online video on a level playing field with traditional TV.

Loyal fans will stick with the NFL and their favorite teams. But there are a lot of casual fans as well, for whom watching a game is a choice for how to spend their time, not a must-see event. As their choices - and the quality of them - continue to increase, largely driven by the broadening adoption of SVOD services, the NFL is going to come up against a very tough competitor.

As last night’s game showed, it’s perilous to conclude anything too early. The NFL’s viewership challenge may not be as steep as overcoming a 25 point deficit with just over a quarter to play. But the league is experiencing strong challenges to its traditional model. Let’s see what plays the NFL calls to reverse the downward momentum for next season.