Banks are not needed to solve duration mismatch. The market will solve it in one of these two ways:
1. Person-to-person (Morpho Midnight, Liquid Lane): an orderbook to price credit.
2. Person-to-pool (Royco): A sustainably incentivized pool of always-on buy-side liquidity.
Coinbase charges 2% as a processing fee for new loans. That's of the borrowed funds, not 2% of the interest! Meanwhile, most onchain protocols struggle to charge anything. Really shows who owns the more valuable asset (distribution).
A lot of DeFi is dead / worthless purely because it exists to sell to a shrinking pool of capital.
Winning in DeFi means finding a way to grow the pie.