Is it even realistic for a company to sell $1000 appliances that last 20 years? I know we can build such an appliance, because they did in the 80s, but can a public company survive selling them?
The worst example of this is kitchen remodels; the average kitchen that is remodeled is not falling apart and absolutely unusable; it's usually a 7-10 year old kitchen that just doesn't "look right".
Cars are an appliance that is more expensive, but they last 20 years these days (average age of a car on the road today is 12 years).
It's actually informative to spend a day where everything you look at, you think about how old it is. This includes things like doors, windows, floors, etc. Most are much older than you might think.
It depends on the thing, but in general I don't think that assumption is terribly valid. The problem is that "viable" and "maximally profitable" are two different things. Companies have decided to chase the latter exclusively -- but that's a choice to satisfy short-term greed, it's not a reflection on what a viable business has to look like.
I think it's more reflective of how much the exercise of capitalism has degraded since those times.