Very few entities have the resources that do what Facebook (or Google or Microsoft) have done, in creating an entire new language (or languages) that suit their

Very few entities have the resources that do what Facebook (or Google or Microsoft) have done, in creating an entire new language (or languages) that suit their particular needs, and in a relatively short time (hack was being used within facebook very quickly). Twitter certainly doesn't have those kinds of resources, but they do/did have the resources to migrate to a language with an existing developer community and existing tooling.