that's strictly not true, at least for many segments. my 1960s Kitchenaid mixer has been used since..the 60s, and if you buy a new Kitchenaid today, don't expect that plastic gear to last very long if you actually take it out and use it.
Furthermore, you probably can buy a mixer for $1000 that has a similar chance of surviving 60 years for $1000.
Why don't you provide an example then? Findig one for $1000+ is the easy part, knowing if it's actually better is not something most people can do.
One interesting thing was a gimmick about heating soup with the blender using solely friction.
I eventually bought a modern plastic refurb which has been a dream. I do think it is a shame that it won't last 50 years.