I happen to have cable again because it was a very nominal increase over cable modem only and because I don't get a very good OTA signal from our apartment.
Prior to this move though, I'd done without cable for ~5 years. I got MLB and NHL direct from the league offerings, and as noted as long as you can get an antenna singal and are willing to go to a bar or a friends house for Monday or Thursday night games the NFL is relatively cordcutter friendly. I would _love_ to give the NFL money directly for something similar to MLB.tv, but don't see it happening anytime soon.
All your local team's games are going to be on free channels. Get a $8 rabbit ears antenna, or if you have a cable modem that provides internet only, get a splitter and plug the other end into TV (that you would normally plug into the cable box). The local free channels (NBC, CBS, FOX, ABC, etc) are going to be available, and that's enough for NFL. You're not going to be ESPN or NFL Network, but if it's your local team, the game will be on a local channel anyway.
This may have been the case at one time, but now the local channels are not available like that from Comcast. You need a cable box to get anything at all.
And many people live in areas that don't get over the air reception, at least not with any commonly available antenna.
NFL is one of the easier ones to go watch at a bar or restaurant because the games are weekly. Other sports with games on almost nightly are a lot harder to go out and watch.
Yeah, the blackout situation on MLB.tv is ludicrous. Living in the home television market of my chosen team, why would I pay to be blacked out on half the games?
Once they finally come around, it will be much easier to convince people to cut the cord.