I think you may be confusing the actual US peak with the world peak. Perhaps they did indeed underestimate technological advances and/or declines in demand caused by recessions etc etc.
Like Hubberts 1995 prediction.
Also as rwwff points out - the real numbers come in over time yet I dont think a decade will be neccessary for us to look back upon a peak.
At this time - if there was a pronounced peakage - we would most definately be aware of it - I dont think you are asking the question for no reason
Have we peaked in production?
Good question - looks like maybe yes and when all is said and done Predicting PO is like playing with hand grenades - getting close will do just fine
I do want to say that Peak Production is ONLY the Traditional signal of the real peak or "halfway" point and I contest that we are well beyond peak at this time. When we peak in production I believe we will be near 60% or higher of total conventional oil depletion.
The proof of this I expect to see in higher then expected decline rates. Technology is a double edged sword in more ways then one.
It is easier to enslave a people that wish to remain free then it is to free a people who wish to remain enslaved.