when regulated interest rates went below inflation during the turn-of-the-80s crisis they responded with money market accounts, fixed-term Certificates of Deposit, risky loaning that bid up real estate value and provoked the S&L crisis, ultimately mergers and the Sarbanes-Oxley end of the depository/investment banking wall, the move to 401(k)s for long-term savings; individual retail deposits aren’t really the things capitalizing banks now and even if you depleted their on-hand stock of bills it wouldn’t be a run, you could still use ATMs and debit cards elsewhere