Decentralization is a direction, not an end state.

If targeting an end state, ask, "decentralised enough for what?"

E.g. If 200 central banks were the only parties to self-custody, is it decentralised enough to avoid capture by a single state? Probably. Is it decentralised enough to separate money and state? Probably not.

What goals do we have for decentralization? Check-in with those to see how much self custody is required.