Microwaves should last for decades, this is the same type of thing that you may have heard your parents complain about "I had a can opener that I got from my mother and it just broke, the five new ones I bought same price all broke within a year".
There is really nothing complex about one. It's a timer connected to some voltage equipment and a couple transformers. But, the way you make it, fused steel, well oiled joints, cheap copper wire barely within tolerance or thick wire able to withstand 2x the amperage, varies wildly. As demand goes up, you build fancy microwave factories with expensive well tested molds that can churn out hundreds of thousands of them...until demand goes down and paying for maintenance and power at the factory no longer make sense, let alone having anyone staff the place or prevent looting and squatting.
So you cut corners and your microwave is made of plastic, every time you use it it fries its own cheap water based glue, and the thing falls apart every 6 months.
That's what he's complaining about. Yeah, capitalism works great assuming constant or increasing demand, but it's really bad at financial planning or literally anything else, and then it creates garbage and human suffering.
I think probably the microwaves in the Soviet Union still probably last decades, because unlike the American ones, there were still people willing to buy and or repair their own. Sure they might be "trash" in build quality, at some point in history, but what matters is not all money.
