Especially because you can get TVs with Roku built-in.

I believe there are TVs that come with AppleTV built-in. I'm not in the market, so I haven't looked, but I suspect they're not the bargain basement Wal-Mart sets.

There are TVs with Apple TV the streaming service, not Apple TV the OS. (Or Apple TV the app.)

https://dcurt.is/apple-tv-all-the-way-down

(Since that piece, they've renamed Apple TV+ to also be "Apple TV".)