I think part of it is that we've had near-zero interest rates for the last dozen or so years. So banks can't make any money from small balance checking accounts

I think part of it is that we've had near-zero interest rates for the last dozen or so years. So banks can't make any money from small balance checking accounts, hence the ubiquity of minimum account balances. The traditional business model of factional reserve retail banking just doesn't work that well with super-low interest rates.