I suppose expense was a factor. At my beauty school I think it was $5.50 for the shampoo set. I can't remember how much a perm plus a set was. Had to have been like $12. I've no idea how much it was in a real salon. I made sure to never work in a salon that catered to the shampoo set crowd.
I loved most of my old ladies in school. I had one awesome old gal named Olga. She would let me do whatever I wanted. Then let me know the next week how it went over with her pals. I suppose most of them are no longer with us by now.