I’ve been thinking in a similar direction recently. I think it was Doctorow that pointed out the decentralization->centralization progression of the web due to the time lag for big players to understanding the value prop and gradually iterate on their offerings (eg Google taking over email with Gmail).
My guess here is that the centralized systems to learn the lessons from crypto will be the Visa, Mastercard, NACHA, and the Fed. Perhaps we’ll see a smart contract platform built into existing exchanges like NASDAQ.
The blockchain bit will fall away for the most part because the big guys will not actually let the “trustless” system become the seat of power in the economy. And you can build all of the business-facing features without a distributed ledger. (Trivial existence proof - just run a private ETH blockchain and expose a public API for it. This is kind of the Ripple approach here, cutting big deals with existing players.) Reversability and “right to deletion” will trump trustless because most of the actual market participants want the former and not the latter.
Note, I think there is a different analysis for the US, EU etc (with functioning, stable economies with huge financial service industries resisting power shifts) and basket-case economies like Argentina and Zimbabwe. Perhaps the people in Argentina will continue to use blockchain as an alternative financial system in the absence of a long-term stable economy. But I don’t think this will be the outcome in the US.