It's under Apache license, and therefore it can be taken closed-source at any moment.

Rust is a language for virtue-signalling, rather than for doing useful work.

Can you clarify what you mean when you say it can be taken closed-source at any moment?

Do you mean that future iterations of the software could be closed source?

As far as I understand, they can't just revoke the existing open source license for the existing already distributed software, and if they did decide to move forward from here with closed source distribution, the community would be free to just fork the existing codebase and continue working on it.

how? as a copyright holder you can at any time relicense code as proprietary of course, but that neither revokes the existing licensed code, nor is at all unique to the apache license?