if "perfect market" outcomes are defined to be just, it's hardly worth keeping the archaic notion of justice at all

That reminds me of Erhard's view of the Soziale MarktWirtschaft: "The market is social".

However, the Social Market Economy was based on strong institutions with legal guarantees. And marketista liberals today live happily with the notion (and fact) of powerful corporate litigation.

Of course, Hayek would agree with your conclusion about the "archaic notion of justice". I think he would say that what the market does is neither just nor injust, that the concept of justice is inapplicable. Presumably, only charity is. See philanthropic billionaires.