At a minimum, the app needs updates to handle breakages caused by OS updates. It needs moderators and other staff for legal reasons since Meta is large enough that there's always a significant liability risk for even a few users. It needs to interact with the main non-VR app unless they want to fully isolate it. Etc.

When I was at Google, I had many of these discussions about cost tradeoffs for products that were https://killedbygoogle.com/