Reusable KYC is stuck because people conflate two different things a verification can be:
1. a judgment ("this person is fine")
2. a set of facts with provenance (who recorded what, when, from where)
Medicine keeps these seperate. Dr Alice saying "Bob is healthy" is a judgment. A blood panel stamped with the lab and date is evidence.
If Bob brings Dr Alice's note to Dr Charlie, Dr charlie cant really lean on it. if Bob gets hurt its Dr Charlie's license on the line not Dr Alice's. So he orders the panel again
That's excatly how the BSA works. every institution owns its own obligation and no contract moves that liability to someone else.
Most "re-usable KYC" proposals are asking regulators to let Dr Charlie rely on Dr Alice's note. Nobody in medicine would propose that. Worse, if every Dr Charlie relies on the same Dr Alice, one bad Dr alice corrupts every file downstream
You dont fix the second opinion problem by making Dr Alice's opinion legally binding. You send the bloodwork.