While did:plc was intended to be centralised from the start and under open governance (https://docs.bsky.app/blog/plc-directory-org), did: provided a framework to adopt other key resolution methods.

As part of the IETF work (https://docs.bsky.app/blog/taking-at-to-ietf) this is a hotly debated area and I’d expect some solid evolution to happen as part of that process, super encourage anyone interested to get involved there!