For what? If they took it away, the source code would still be there if someone wanted to fork it. Not to mention removing TypeScript from an application is relatively trivial.
They’re not that dumb, to just pull it completely. That would obviously result in a successful fork.
Companies usually start with e.g. the BUSL, so source-available but proprietary restrictions.
For TypeScript/Microsoft, I could imagine some variation of their EEE playbook.
But really, the whole point of avoiding Microsoft et al, is that I don’t want to think about, how they could fuck this whole thing up. They’ve proven quite creative in this regard for as long as they’ve existed.