Brief Existances

Some things that seem like they will always be around suddenly aren't anymore. Take for instance the once ubiquitous mens briefcase. At one time it was unthinkable that a business man could be without one. Now in the age of computers and electronic files, they simply aren't used all that much anymore. Some still have them, but for the most part they are a part of the past. I wonder what we have today that will seem totally useless and old fashioned 20 years from now? Aside from technology which is always changing very quickly of course. My guess is electricity generated outside the home. I think eventually, all houses will be built in such a way to create all the energy the occupants could need.