I've a parallel theory that there's a hidden wage decline in service jobs where the move to computerized and card-based payments severely reduced the opportunity for service workers to easily steal from their jobs.

I saw this firsthand with a pizza shop that went to computerized ordering from paper tickets. The drivers could no longer "lose" tickets and pocket the cash payment (resulting in a wage loss of ~$10/hour or more).

I've anecdotally heard similar from lots of folks that used to work fast food and service jobs.