They will still need someone to empty trash, clean the trash in the parking lots etc. McD's and others have automated beverage fillers at the to go window.

Wally World has self-pay and many stores have increased the number of self-pay lines. They began with a couple but have increased the amount. They know that by reducing the live cashiers and creating lines that people will go to the self pay yet continue to patronize Walmart because of low prices. You'll have a choice, wait in line for service or do it yourself. 1 employee monitors 8 self-pay stations at many Wal marts. I'd call that a success.