> What on earth do you do with that many devs on a project like Messenger?

The technical and organizational framework they operate under is so complex and full of jank that developer velocity slows to a crawl whenever a new feature comes down the pike. It's easier to throw a new pod of nerds at the problem than retask, and the reason they come in a pod is that there's nothing in the job long-term for anyone with the sort of intelligence they're asking for.

From my perspective, Twitter was a question of how many people you need to keep the lights on at an organization with low data rate/value. Musk could kill any non-devops department or project he wanted to because a social media company just doesn't have that many existential situations.