There are many things that people think will "change the world" that don't end up doing much or even happening. Sometimes we think "this would be a cool idea", but there are reasons that they don't succeed, or even happen.
I think it's instructive to look back on things and see why.
For example, let's take the idea of videophones. It seemed like a logical progression from phones, right? We started with radio - voice only - and moved to TV - voice with video. Why not start with telephones and move to videophones?
Well, because people don't want to get dressed, or shower, to talk on the phone.
Seems like a great, logical response, but people invested millions of dollars in this technology anyway. Now, though we have cell phones that take video, and we have Web based videoconferencing. Will video phones ever happen? It's kind of doubtful at this point.
Warning: Language as always on cracked.com is a little, um, raw.