Mutual funds, the most legible way to get an estimate of the holding cost of securities (since they are required to transact at net asset value) routinely charge between 0.2-1% fees, depending on size and asset class.

Clearinghouses, transfer agents, and cash management firms don't work for free, which is the problem that cryptocurrencies explicitly solve; neither do compliance, KYC, fraud, etc., which most cryptocurrency protocols elide altogether.