I know what you mean that it seems there are new traditional TV channels being added often. I also think with all of the streaming channel options that the concept of "TV channel" has changed a lot since there are multiple ways to receive, view and pay for broadcast content.
I don't have cable TV, but I use an Apple TV streaming box which is like a Roku. This gives me access to iTunes content, Netflix, HBO Now, Showtime, ABC, and many more channels that I can add to it. To view content for those channels, one needs either a monthly subscription, or in the case of iTunes, to buy or rent a movie or buy a TV series or single episodes.
Those channels get added by going to the manufacturer's app store, and the manufacturer controls what content is available on it. For example, you can't get iTunes content on a Roku, and you can't get Amazon streaming content on an Apple TV.
I have a Roku that's now sitting in a drawer, and my PS4 also has those streaming channels available too, but I just use the Apple TV as my streaming box, one single centralized source. If I want to add an Amazon Prime subscription, I'd have to hook up the Roku as well. I could just watch all of it on my laptop too, but it's not as relaxing as kicking back with a big screen.
How's that for too much detail?