> Not everyone has Facebook's budget or resources to upgrade every 2 months. Even if you're FB, dedicating the engineering time to upgrading/testing/deploying

> Not everyone has Facebook's budget or resources to upgrade every 2 months. Even if you're FB, dedicating the engineering time to upgrading/testing/deploying 15k+ components by making a breaking change would be madness. Anecdotally, when the React team breaks something (rare) a lot of people internally start yelling, and it never makes it into the releases. FB makes for one-hell of an integration test environment.