They did often use better refrigerant back in the day, but it is refrigerant we don't use now because it is either highly poisonous or hell on the ozone layer.

They did often use better refrigerant back in the day, but it is refrigerant we don't use now because it is either highly poisonous or hell on the ozone layer. The compressor itself wasn't often all that efficient mechanically, but the good refrigerant helps make up for it, but also there is only so much to gain out of compressor efficiency. The biggest problem with old fridges is they were insulated like absolute garbage. Not only is the insulation often super thin, but the steel shell on the inside was rarely separated from the steel shell on the outside leading to a lot of heat transfer. So even with it closed they ran constantly almost like you did have the door open all the time. You also have to consider its cooling capacity, you only need a little bit of cooling 95% of the time, but when you put fresh groceries in it or water in the fridge, until those are cooled down they are heating up everything else in the fridge and so stuff will spoil faster/easier. Some older fridges might take a long time to cool everything down if you put in more than a single item at a time. But really, most fridge breakdowns are not because of a compressor failure or anything major, 99% of the time it is some simple electronic component. A simple bad capacitor can prevent your fridge compressor from kicking in. Or a thermocouple could go bad and not tell it to turn on when it should. Both of those parts cost like $2 to produce, but of course they choose more proprietary designs and configurations to make a generic fix more difficult which lets them markup the parts on prices. Which has the side effect of convincing more people to just buy new because they don't know if the 1500% marked up proprietary part was the only part near failure, and they don't have the knowledge or confidence to start tinkering on their refrigerator before they lose all their potential savings on spoiled food, or use an appliance repairman who will add on $200+ onto the inflated parts prices because they don't want the liability taken upon themselves if they were not using direct replacement parts.