Planned obsolescence can be a good thing. Cans from the fifties and sixties still work. Nobody wants to use them; they are heavy, uncomfortable, have poor performance, need an amp to drive, and use huge old school connectors. They are from a time when music was enjoyed seated in one place.

Products that fail prematurely or wear out while the owner still wants them are poorly designed. The pinnacle of design is a product that works flawlessly until the day you are through with it, at which point every part fails simultaneously. Such a product wasted no excess material in being over-engineered, nor consumed exotic high performance materials when they were unwarranted, nor repair visits, nor extra fuel in transport.