One thing that has been predicted for some time - and let's be frank, it doesn't take a rocket scientist to see we are on the cusp of this one - virtual worlds so real that it competes directly with the real world.
Look at where gaming is going. Naturally, most of those who predicted it talked about it as having the same devastating results on people and our culture as drugs.
I agree with you that virtual reality is very near. Not too long ago, in fact, I was going to post an article about current advances toward VR, but when I hit post I was told that the source couldn't be posted on FR.
On another note, the biggest factor that holds back progress is just inertia - most people can only handle so much change all at once. Then also, you have compatibility issues when everything is geared one way and it's more expensive to transition to the better product/process than to just keep the inferior but entrenched product/process.
Take something as simple as light bulbs. We now have far more efficient and aesthetic LED lighting technology than the ordinary incandescent bulb that we're all accustomed to. If it were based on just the best product, incandescent bulbs would have already gone the way of kerosene lamps, but because they're entrenched, of course, it'll be a long time before that happens.
Another good example is operating systems, or other types of software. The prime directive of Microsoft, for instance, is backward compatibility, where each new Windows would be backward compatible with past versions of Windows. If I'm not mistaken, Windows Vista will be the first that disregards backward compatibility to a considerable extent (iirc, XP did to a slighter extent, but Vista will much more so). In any case, the requirement for backward compatibility has inevitably held back the advance of computer tech, but if you totally threw backward compatibility out then it would not be economically viable, because not enough people would buy it.