There's a bit of survivorship bias going on here though. The only appliances still working from more than (X number of years) ago are going to by definition be

There's a bit of survivorship bias going on here though. The only appliances still working from more than (X number of years) ago are going to by definition be those that were built to last for more than (X number of years). So your only reference point is seeing that all the older appliances seem to be built to last. You'd need to do research on all the options that haven't lasted to today to find out if modern stuff really does break faster, and that's much harder to do.