Hack has become essentially a domain-specific language for the frameworks used at Meta. They evolve together. There's no going back to PHP because there's no re

Hack has become essentially a domain-specific language for the frameworks used at Meta. They evolve together. There's no going back to PHP because there's no reason to rewrite the frameworks and give up on the flexibility afforded by being able to tweak the language to fit the framework. It's basically the same situation as Apple has with Swift. They'd never switch from Swift to C++, no matter what features were added to the language.