This is a good point, and the banking system is certainly bloated - just before the GFC more than a third of US GDP went to the financial sector, WTF. However,

This is a good point, and the banking system is certainly bloated - just before the GFC more than a third of US GDP went to the financial sector, WTF. However, the traditional banking system also performs way more functions than crypto and DeFi, and I very much doubt that DeFi can provide them. Lastly, disrupting banking with good old Fintech would be great, as it is vastly more efficient than blockchain.