The answer to one of life's great questions…
Why are there always so few cashiers in shops, banks, and post offices and so many un-staffed tills?
It's because multiple cashiers offer no more benefit over no cashiers than one does.
Allow me to explain…
If there are no cashiers, no people are being served.
If there is one cashier, then people are being served at a certain rate, but this rate if infinitely bigger than no serving.
If there are two cashiers, then in theory people are served twice as fast as one cashier, but twice infinity is still infinity.
Therefore, once you have one cashier, there is no further benefit gained by adding more cashiers.