"In most civilised nations (New Zealand for only one example), in 2011, you scan the goods yourself with a hand scanner as you pick them off the shelves."

Yes...we have a few stores like that, but they have NOT figured out how to handle produce** easily, and it is expensive to set up the computer system & hardware for it, and we have such a diverse demographic that explaining the system in 14 languages is daunting!
The GUI (graphical user interface) at the register is awkward, as there are about 4 screens and scanning devices to follow and IF anything goes wrong, you must wait for a harried store clerk who has to monitor about 5 counters.
We do have lots of credit/debit swiping devices, and I seldom see actual check-writing these days....but there is a LONG way to go to gradually educate large metropolitan areas with 6-7 different chains, all with slightly different register systems.

I'd LOVE to shop in a system like New Zealand where it likely more uniform.

(**..Produce must be either all pre-wrapped --blah!--or stickers placed on individual items with a code and weighed at the register.

I see why store want to reduce total employees and send us all thru machines which do not require breaks or lunch hours, but frankly, the human element, with clerks who know the store & products, can make it all work better.
I worked for years in grocery stores during my high school & college years, and can SEE what really works 'better' and what is nothing but cost-cutting devices for the stores.