I recently turned on my old Fire TV and was surprised at the available apps though it was unbearable to navigate cause of its age I guess. They have every network from A&E to Showtime in their ecosystem and they work great unlike sideloaded apps on ATV. I feel that Google needs to step it up if they want to make ATV a real thing. I love my Shield TV, just wish ATV had the same amount of support that the Fire TV has.
/end rant
Google doesn't make the apps. The code is available. Contact the company if you want them to make an app.