It is not advantageous for anyone, neither the buyer nor the manufacturer, to develop and build devices that would last for decades.
I have to clearly disagree with you on this occasion.
The lack of durability in many devices is not due to the fact that constant innovations take place that significantly improve existing technology every few years (the better is the enemy of the good and therefore it should not be too durable). The washing machines you bought five years ago and the ones you will buy in five years do not differ significantly – the significance is pretended by lobbies here, that is marketing nonsense.
And it is similar with coffee machines, microwaves, etc. Genuine, disruptive shifts by innovation do not depend on the expiration of the durability of the previous technology anyway. What is clearly better will prevail.
And I consider it wrong that innovations arise when (or despite) one artificially keeps the market for the old technology fresh through obsolescence. Why should one go into something completely new if the old one can be marketed so well along wear and tear?
This is good for number crunchers in the high-pile carpets of some boardroom floors. Not for the enthusiastic developer. And certainly not for the customer. Why it should be different, you would have to explain.