Okay, I'll accept your argument that long term and short term economic predictions are not equivalent, leaving aside for the moment the question of where one ends and the other begins.

I have never heard of a long-term economic prediction that was proven to be accurate. On inspection, most professional predictions are "adjusted" through time.

Economics is fundamentally unpredictable. There are far to many unplanned, unexpected, and unpredictable elements. I cannot think of any decadal interval in the past 100 years in which some expected event or invention didn't upset the prevailing expectations. I see no reason to suppose that the future wont be at least as unpredictable. To me it is arrogant to presume otherwise.

B