Doubt it. Solana will be an important player in payments but it has a noisy neighbour problem inspite of local fee markets once alon coins or NFTs ring again. Also fintechs want compliance not neutrality. Specialized payments chains eg Tempo, @noble_xyz and Arc will win this

DTCCs primary role is registry, which allows them to net transactions. The street has $50B of equity capital at DTCC on any given day. That isn't necessary in an atomically settled limit order book on blockchain. The registry service is trivial - a blockchain TA just tracks the token across wallet addresses. It's less involved - and much cheaper - than what a TA does today. You will still have custodians because the SEC requires that of funds (having a QC). You'll still have market makers. Broker dealers are less relevant because you don't need an introducing broker to attach to the ATS to trade - you just need a wallet that will work. Your custodian could displace your broker dealer, for example. No dumb quesitons - this is all greenfield and some of it will be learn as we go - but the change is coming.