i believe this began with self-service markets, doing away with clerks and relying on customers to find items themselves... followed closely by self-service gasoline stations, where you pump your own...this replaced tons of workers, and the goods dealt with by "self" were not only the same price, but usually more expensive in the bargain ...
this is an discussion area that is easy to open up economic questions about, especially with people old enough to remember when workers did some of the jobs that consumer-customers do now... while paying more money for the product, as in, where did the "savings" go, by ridding the firm of an employee?
fs