I also had the distinct impression that the overwhelming feedback regarding the default implementation was negative, e.g. SE-0261: Identifiable Protocol - #35 by Lantua
It is unfortunate that this has been completely ignored and the proposal has not even been extended with these objections in the alternatives section.
Now stating that this was discussed but not proposed is a bit of a cyclic argument... it has certainly been proposed by the community.
I also don‘t understand the strong desire to keep this default implementation as weiting it for the rare cases where it is needed is trivial (I don‘t share the view that ObjectIdentifier is obscure knowledge).