[pessimizer]

A specific technological change: writing (and printing.) We were able to remember longer spans more accurately than could be done by memorization and the passing of that knowledge from old to young. Reversions occur due to the active destruction of recorded history through war and religion. When the retention of novelty depends on the health of a relatively small number of people, as a society you're perpetually rediscovering instead of discovering.

Now our problem is even having the ability to assimilate enough established knowledge during a lifetime to have a chance of making any novel contribution. The obvious endgame to AI is a dream of being able to assimilate information and innovate indefinitely.