First, it's often more expensive than people can afford. Most relatives I know are "stuck" buying low-grade appliances/furniture just because they can't afford more, and they know they will have to replace it in 4-5 years.

Second: fashion/mode/trend. I was surprised to see many people throwing functional appliances, computers and even furniture just because it was outdated, not trending. such as "My old cell phone still works but I'd pass for a retarded if I don't show up my latest iPhone". Same for furniture, curtains, chairs and tables that are still good, but people often change because they want to renew the appearance in their homes. Do many of you still use good'old wooden furniture of your grand-parents in your home?

So, I'm not convinced the "50 years" model would be ideal for everything. Because human nature.

A 10 years model would be great, imho.