Fifty is the New Twenty

Yes, the title is "Fifty is the New Twenty," but this isn't about age.  It's about money, as in $50 is the new $20.

The ATM I use offers both $10 bills and $20 bills.  It will let you withdraw just $10 if you needed to buy just a couple of cheap greeting cards and a box of mints at the drug store.  But if you want to buy just 3/4 of a tank of gas, you'll want at least $50.

So why does this particular bank still offer tens and twenties when twenties and fifties would be more appropriate for today's cost of living?  And why is the limit on total withdrawal somewhere under $400 when you can spend $350 just at the grocery store?  And why am I asking you this?

An ATM stuffed with $20 and $50 dollar bills would impose a minimum withdrawal of $50, but it would still allow for ten-dollar increments.

Of course this would require paying programmers to update the ATM software.  What incentive would a bank have to do this?  Maybe the bank could demonstrate that it's a forward-thinking, quick-on-its-feet, innovative institution.