The YouTube app has never been good and never felt like a native app -- it's a wrapper around web tech.
More importantly for games, though, is the awful storage architecture around the TV boxes. Games have to slice themselves up into 2GB storage chunks, which can be purged from the system whenever the game isn't actively running. The game has to be aware of missing chunks and download them on-demand.
It makes open-world games nearly impossible, and it makes anything with significant storage requirements effectively impossible. As much as Apple likes to push the iOS port of Death Stranding, that game cannot run on tvOS as currently architected for that reason.
More importantly for games, though, is the awful storage architecture around the TV boxes. Games have to slice themselves up into 2GB storage chunks, which can be purged from the system whenever the game isn't actively running. The game has to be aware of missing chunks and download them on-demand.
It makes open-world games nearly impossible, and it makes anything with significant storage requirements effectively impossible. As much as Apple likes to push the iOS port of Death Stranding, that game cannot run on tvOS as currently architected for that reason.