The registers get more self sufficient as the software matures. The security systems become cheaper and more accurate to eliminate the lackluster security effect a clerk has standing there. The clerk is removed entirely. Then the shelf stocking is automated with computer vision and maybe magnetized sticker guide rails in the floors.
And then people realize its stupid to go to a store to buy stuff when you can virtually tour a mall of everything and have whatever you want shipped to you. You order it, it goes through computers without ever interacting with a person, and a manufacturer ships you it instantly.
And that process gets automated too. The transport goes from self driving autos transporting your goods using standardized automated transfer mechanisms to your automated mailbox to a fabricator in your own home that comes from Star Trek.
None of that (besides the fabricator part at the end, thats going a bit heavy) is nothing novel or even new. It exists. It just takes market pressure and time to make it economical to implement and for culture to accept it. Because it is more efficient, and it will inevitably happen because its better in every way except the "but people aren't doing it!" angle. It does not take AI sentience to move boxes or see dirt on a floor through dictionary lookup and fuzzy logic processing.