I'm an ex-Rams fan and St. Louis already made that choice - hell no. Imo the ratings decline primarily has to do with the following:

(1) General oversaturation of football in general. People are getting burnt out on the nonstop NFL talk in sports media, Thursday night football, and the expansion of non-Saturday college games.
(2) Natural changes in media consumption. TV ratings are down across the board, not just the NFL; the availability of streaming options and the proliferation of condensed highlights are shifting viewing habits from sitting down for four hours in favor of four-minute snippets.
(3) Decline in quality of play. The game just isn't fun to watch, you're seeing blowouts left and right with shrinking parity as well.
(4) Bad PR. The NFL has consistently made bad decisions in search of profit, has failed to address player discipline problems, lets bad owners F over cities in search of new stadiums or markets, and does little to nothing about player safety. After a while it just pushes people away.
(5) Pricing. Games are too expensive for the common fan, the game has been getting corporatized for some time now.

I don't like the kneeling either, but honestly I think the controversy is mostly the extra fuel on the fire instead of the root cause. Even if the stupidity surrounding that never started you'd still see the factors listed above causing lower ratings.