I think it's partly the consumerism culture, and because companies attempt to cost cut at every level, we could use good plastic be we save 5 cents per unit if we use the cheaper plastic. We could source good ceramics for our power supply, nah lets go with the cheaper ones. If you go look at products made 30+ years ago compared to today, the difference is really noticeable. Back then products were made to be repaired. Today products are made to be disposed of an replaced.I'm not sure if it's 'for a lifetime', but yeah. Crippleware is provably a thing, so it wouldn't surprise me if products were designed to degrade faster somehow.
Go to a Backyard sale and pick up something like an old walkman. It's mostly metal, instead of springs and rubber bands for many actions, it uses pneumatics. It's designed to be used over a long period of time and kept. If something goes wrong, it's meant to be opened up and repaired.