> Any idea what changed?

sadly, or fortunately I am not at facebook anymore, so I don't have the inside track on what changed.

> Is Facebook really set up such that one person's whim is the single point of failure?

Kinda. Zuck sets direction, and he has key interests. The thing that really makes him happy is cutting edge research and new features. The thing that passes him by completely is product experience. Oculus is a great example of that. The user experience was/is trash. the time to fun is/was too high and was for a long time. Carmak spent ages saying "we can't compete on hardware specs, we can compete on ecosystem and experience" he lost that argument.

Outside of zuck there are only a few areas that actually make decisions and communicate them properly, one is monetisation/advertising and the other is Infra planning. _Everything_ else relies on people churning initiatives and seeing what sticks. With loose coordination at the centre based on who know who and who manages to convince others that "this is a Zuck priority, or related to one"

It felt very much like having a Boy king. The Boy king liked playing with toys, and if you made a toy for the king you were in favour. The boring parts were handled by "evil advisors" who are there because they don;t threaten the king's power. Everyone around the boy king is there to gain favour.

> the time to fun is/was too high and was for a long time.

Yup - I got one for the other half as a present... like an hour and a half / two hours into setup/onboarding, they lost interest, it went back in the box and never came out again. :(