Keys are already obsolete, as there are many new effortless ways to validate individuals. Technology can, for instance, read a card through the salts on your skin (or something like that), allowing some doors to be like automatic ones, but only for people who are allowed in. There are also many ways to make sure you don't lose your remote (sensor arrays like Aspen). The real reason all your futuristic technological dreams don't exist right now is not because its not possible or it hasn't been done - its because its expensive. To make a braingate for 6 billion people, let alone arms and legs and such, would be incredibly expensive in terms of resources, manpower, and time. Economically and industrially speaking, such fantasies are still very out of reach, even though the technology is so close and tangible. Some people may have robotic arms and legs (that won't go to 60 mph), but say 10 or 20 thousand people out of 6 billion really isn't that groundbreaking, although the advance may seem so due to the "prophetic" television and video games.