The Kenmore Combo's Permanent Press cycle used hot wash also, which sounded horrible until you consider all that had to be heated up. By the time the wash was going good, the water was not steaming hot. I think a lot of the perma-press cycles were geared to dress shirts. These were still the days of "Ring Around the Collar", greasy hair "tonics" and less than daily shampooing among men and the clothing, detergent and washer makers wanted to see the best results where they would be noticed most.
The sad trick that has been pulled on the consumer is this 100% cotton crap; like any polyester is a carcinogen. The strength of the synthetic fiber really helped keep cotton from wearing, fraying and going limp. Now you buy 100% cotton and have to replace good pants every year or so because the edges of pockets, cuffs and creases start to wear out, even if you turn them inside out when laundering them. Polyester got a bad reputation from leisure suits and shirts that absorbed no perspiration so you dripped, smelled and were chilled by cold, wet fabric. If you think about it, polyester also seemed to go by the wayside when oil took a couple of price hikes by the early 80s. Before that, it had been cheaper than cotton. Once cotton could be turned into garments in the same third-world countries where it was grown, we got stuck with a more iffy version of perma-press called "wrinkle resistant" and other terms that did not promise as much. It was more the resin-treated wash 'n wear fabrics that were damaged by heat, cotton/poly could take it in both the washer and dryer. The owner's manual from the 1958 Lady goes into great detail about fibers, fabrics and finishes and which of the Wash 'n Wear settings, C, D, or E, or F for the Delicate cycle, should be used. If you check the catalogs of work uniform manufacturers, their shirts and pants that are Permanent Press are still the cotton/poly blend because they stand up to hard wear and hardware without wearing out.