Maybe both...
Indeed it may be both the period of time and (at the time) a distinguishing factor between standard and deluxe models.
I based my 1970 date on the fact that my father worked for Hotpoint and I would go to the General Electric factory store at about that time. I do recall the cloth cords becoming rarer at the early 1970s. The GE catalogs show no cloth cords by 1972.
However, there was nothing inherently wrong with cloth cords. I would suppose some economy brands ran cloth cords for a while after, perhaps to use up old stock.
Unlike the transition to digital television, there was no date where the country transitioned out of cloth cords! LOL!
