I cut cable last year and I saw plenty of football OTA. My favorite team was on OTA broadcasts something like 13 of 16 weeks and it would have been really easy to make arrangements to see the other three games. I could park my butt in front of the TV almost continuously from 12:30 PM to midnight on Sunday and watch football if I so desired.
But being a Redskins fan, I had very little reason to watch NFL football last year!
There was plenty of good college football OTA as well. What I really missed was seeing the VCU Rams play basketball, as almost all of their games were on cable. But you know what, I got over it. I went to several games in person (with the cash I didn't spend on cable), went to friends houses, listened on the radio some, the occasional sports bar. It's doable. It is also a good way to put some healthy distance between yourself and the game. It's just an entertainment medium after all.