I just saw a commercial that said "CBS is off the air." Is this true or was it said just to trick people into buying CBS All Access?
I think you just misunderstood the commercial. CBS is on the cable and "over the air" using an antenna. You never stated in what area you are living in.
Sometimes a local station (in your case the CBS network one) might be negotiating for a better deal with: cable, or satellite provider, in your area. They might be hoping for people to complain on their behalf. I have never seen any of our locals ever follow through on that threat.