That and also in the old days we have undocumented workers filling in those jobs. I think a lot of them either decided (or someone else decided for them) to move back home.This is the true cause of the "labor shortage". Lots of people who've become out of work over the last year have realized how miserable working a low paying retail/food service job where you have no benefits, make peanuts, and get treated like crap by customers, and have realized that they are worth more than that. It's not that people don't want to work, it's that people don't want to work for the pay/benefits you're offering them to put up with the bs that you do as a retail/food service employee... People have wised up. I know a few people that have used this as a chance to change careers, go back to school, learn a new skill to take a new, higher paying job.
The better work ethics ones who are legal to work entered the higher paying field like constructions and trades, or janitorials (no need to deal with insulting customers, safer working environment, more predictable schedule), or are all hired to do private at home nanny. Why would you go work at McD when any of the above jobs pay you better and or treats you better?
Most lower paying retail staffs will either get automated (or self services), or stores shrunk down to sell fewer items, take it or leave it style, and let those exotic stuff to be bought online only.