This is not accurate, FaceTime has Share Play. Any app that leverages it can build a synced entertainment. Example out of the box, Apple TV, Freeform, Apple Music.
I wish the SDK for Share Play was not tied with FaceTime, since it limits you to only people you have their iCloud email or phone number to. Big Screen on Quest was a great app that leveraged the idea of multiple users in the same VR session, based on interest, Quest just lacked the quality.
https://support.apple.com/guide/iphone/shareplay-watch-liste...