To be fair, it's a bit more subtle than that. There's a level of survivor bias involved - all the unreliable appliances from the 50s-70s have long since been hauled off to scrap metal recycling, so what's left are the long-lived ones.
Modern electronics certainly can be made with much higher reliability than their mid-century ancestors, but the driving factor that prevents this is aggressive cost cutting that happily shaves pennies off COGS to shift the statistical distribution to the left. Unless consumers are willing to pay more for long-lived devices, this is doomed to continue.
Because the mechanism by which most contemporary appliances turn into junk is the "control board" "breaking" (which seems like it must be flash endurance, meaning directly planned obsolescence) and is unrelated to survivorship bias - old machines used mechanical timers, and even when they started using solid state it was simple. I'd say it's actually fallacious to point to survivorship bias, because old machines were built with parts that could either be repaired or replaced.
I've got a relative's dryer right now that's acting up. Do I really want to do the work of calling around to a bunch of repair guys to find out which one won't charge me a fee to come out and say "it's going to cost more to fix than to buy a new one, and we can have the new one installed and delivered tomorrow" ? I've heard this trash spiel so many times at this point I don't even care to try engaging, despite not even having to pay for it myself.
No, I'll spend the 20 minutes taking a few screws off and looking at the thing. Then order parts. Then next week, an hour or two to replace the part. Then it will likely be sorted for the next decade, but if it does break again it will continue to be repairable rather than effectively a consumable.
Modern electronics certainly can be made with much higher reliability than their mid-century ancestors, but the driving factor that prevents this is aggressive cost cutting that happily shaves pennies off COGS to shift the statistical distribution to the left. Unless consumers are willing to pay more for long-lived devices, this is doomed to continue.