You can't automate to a level to replace them. You can automate order taking, but the human order taker who does it also cleans the store, fills and packages orders, leaves the store to clean the outside and dumps trash, answers customer questions about food, troubleshoots register issues, balances their drawer, and more.

And something as simple as checking straws and napkins or making sure the floor by the soda machine is clean can't be automated cheaply. Automation in general is too fragile to handle the demands of that kind of work.