[nabla9]

Amara's law: "We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run."

Amara's law seems like a common human fallacy but it's also true that it's very hard to estimate correctly a growing trend. We have something that is obviously important and will have profound effect, but even small error in the estimates of technological proliferation can lead to 5-25 year time differences.

Another thing is the hype from outside the field. There are more people outside the field hyping it up than there are people inside hyping it. Investors, media and marketing are are powerful force when they jump in and they don't cool down easily.