Old school dishwashers on market from 1950's through good part of 1960's wanted incoming hot water at minimum of 140F but could take temps of 160F. Well within optimal range for standard chlorine bleach dishwasher detergents of day.
They also had on average many more changes of water (my GE Mobile Maid "Normal" is "W-R-W-R-R" which kept water hot. It has a heater but that only helps prevent water from cooling off too much and helps with drying.
Many housewives then soon learned to scrape dishes well and perhaps pre-rinse. Latter was especially true if dishes were coated with protein substances like milk, egg, etc.. Hot water sets those things making it hard to shift, even with most forceful spray and chlorine bleach (latter attacks protein).