Comcast has declined to comment.

The long wait might stem from conditions surrounding Comcast's NBCUniversal takeover. The company can't offer services based solely around its own content until September 2018. It would have to either include video from outside sources or else sit tight. Either is an option, however. As tipsters revealed not long ago, Comcast has obtained national rights for multiple cable networks in case it wants an equivalent to multi-network services like DirecTV Now, PlayStation Vue or Sling TV.

It's easy to see this happening. Rival telecoms also want in on streaming TV, and Comcast in particular has been warming up to online video. And it likely wants a safety net given that it only just resumed adding subscribers in 2016 after 9 years of losses through cord-cutting and economic hardship. If internet video eventually supplants cable, Comcast will want to be ready.

The question is whether or not an NBC-centric service would find broad appeal. While it would be alluring to cord cutters who regularly watch NBC shows, it might not be as compelling if you can't find either internet-exclusive material (as with CBS) or premium shows that normally require an expensive cable package (see: HBO). Unless both the price and content are just right, it may be more tempting to sign up for universal TV services that offer a wider selection.