Nothing sinister here, really, and the answer is given in the article. NFL sells that footage to individual teams for coaching purposes.
In high school (yeah, I was a geek) I filmed all the games for the football team from the top deck covering half the field at a time. I, of course, wanted to zoom in to where the action was but the coaches wanted to be able to analyze coverages, offensive and defensive alignments. Made sense.
the NFL doesn’t allow local TV stations to film highlights
Now that NFL films is (presumably) shooting video, it’d be of trivial difficulty to offer a streaming pay per view “all 22” feed of the game of the week.
They’re a bit off on how the TV coverage is done. Even with all the gee whiz cable cameras, most of the basic shots are from the same midfield and 20’s press box positions we’ve used for 50 years. The lenses are a lot better now, though.