I believe that the drop is due to ads made to target a demographic that is not that which watches football. Allstate Insurance, for example, once a proud, esteemed American Company now presents this as the face of it's company in ads during football:
and thats just one example of many....ads that feature flamboyantly gay characters, blood-curdling screaming and hollering characters totally spazzing out. Millennials are producing TV ads for the Millennial Demographic and its seems obvious that Far-Leaning Left Millennials are using TV ads as a means to express their beliefs and, at the same time, effectively "punish" that demographic that disagrees with what they believe.
Which is the demographic that watches football. "Macho" "CisGender" etc. activities and those who value these are the absolute enemy of the Feminists, LGBTwhatever and Far-Left leaning Liberals that (it should be obvious from the type of characters used in ads) are in charge of content of the ads.
They're using these ads as bludgeons and sane rational white guys (longtime football viewers) are getting driven away by the psychologically terrorizing content of their commercials.
Why should the act of merely watching a football game cause one to be deserving of the absolutely horrific punishment that it is to have to suffer seeing this:
there are guys that find themselves in a place that having to see that ^^^ and the multitudes of other Black or Gay and/or shrill completely Vexating characters in the ads has become just too high a price to have to pay. To watch Football.