Apple has been signalling their intentions for several versions of tvOS. First, they introduced the TV app, allowing other apps to list their contents within it. Then, they switched the function of the Home button on the remote to go into the AppleTV app instead of the app screen, then they introduced Channels, replacing apps with channels within the app, now they’re deprecating their own apps and bringing them into the TV app.
For a secretive company, Apple does tend to show what they’re doing if you just look.
I don’t expect apps to disappear but the AppleTV app absolutely looks to be on its way to becoming the home screen. Maybe there’ll be an Apps button that takes you to the existing apps screen or an app list but everything Apple has been doing over the last few versions of tvOS has been devaluing apps. They were never the hit Apple intended them to be.
But we have never seen a precedent for channels used the way you are referring to. Making arcade games and Weather channels would absolutely dilute the meaning of a channel. Channels are other streaming services which are built directly into TV app. Like HBO, Starz, etc. How much sense would it make to have a channel called "Angry Birds," another called "Castle Defenders," and then after that CBS All Access? Games are not channels, period. And it is bonkers to stuff everything into TV when it doesn't belong there.
There's a 0% chance that Apple does away with the Home screen.
Apple channels are the same concept as Amazon channels. Or Hulu channels. Hulu and Amazon also have a ton (and even more than Apple) of third party apps/channels integrated into Prime and Hulu. Apple is just cribbing that idea. What we don't see, anywhere, is arcade games, or news/etc. apps globbed into the TV/movie services of any streaming service. TV is for TV. The Home screen and App store is for Apps. The App store is far too lucrative to Apple and all the other developers to be removed, and the Home screen will continue to be the way it is.
Apple sees the Apple TV as a family multimedia hub, connecting Apple to a plethora of different viewing uses on a TV. Including reading magazines, newspapers, articles on the TV screen, including listening to Music, podcasts, etc. Including looking at the Weather, stocks, etc., including watching streaming services, including TV/Movies in the TV app. Including games in Apple Arcade and standalone. By reducing it all to a TV app, you are cutting off 3/4 of the potential uses Apple intends with this device. And you are stuffing WAYYYYY too much into an app that was never intended to cover that function.