Wht we've found in the last couple of years is that many cable TV providers (particularly Comcast) are going for their own proprietary digitisation. We've stayed at several CGs is western WA whose monopoly cable provider is Comcast and it's been a real circus.
We have Comcast in the S&B and each of the three outlets in the house has to have one of their decoders. As I understand it, no TV sets on the market have the capability to process Comcast signals without their decoder. It may be the same with other cable companies. Obviously, a CG can't afford to provide a decoder to every guest.
We concluded that TV wasn't that important when we're on a trip. If we can get TV service, fine - if not we'll rely on radio. At least the FCC hasn't allowed the media to screw that up!