pg, I don’t think the analogy works for other reasons, but just to nitpick: clients have ample legal recourse if their attorney did something in violation of these codes of ethics, procedures and civil law, NOT if they are dissatisfied with the outcome. If the outcome is unsuccessful, they have absolutely no legal recourse to recoup the fee for services, so long as the payment was not predicated on successful outcome (as is sometimes the case).
So unless the shadchan violated civil law or ethics/morals (I’m sure it can happen), “ample legal recourse” in the case of a lawyer has no bearing on this conversation.