There’s a wip extension of PLC which aims to make it fully decentralized, called did:plc:bft.
Emerging specification and reference implementation by @gbl08ma.com in progress here: https://tangled.org/gbl08ma.com/didplcbft
PLC implementation isn’t the responsibility of a PDS per se, but it is however up to the PDS implementer to decide whether to support an alternative did-method. I know you tranquil folk like to be on the cutting edge, so I’m putting this issue up for public deliberation.
I just want to clarify that didplcbft is not meant to be a new DID method but instead an alternative way to "interact" with did:plc identifiers, with the (very unlikely) long term possibility of it becoming what did:plc is (pending an update to the did:plc spec so that plc.directory is not the only canonical API endpoint, of course).
Should I get to the point where there's a functioning didplcbft network online (which would still defer authority to plc.directory), then, in principle, all any piece of software will have to do in order to "support didplcbft," is allow for did:plc identities to be resolved/updated through an endpoint other than plc.directory. This is something you might want to support regardless of didplcbft existing: I believe other (non-P2P-based) unofficial PLC mirrors already exist, and it is nice when people can elect to use them.