I would argue that this difficulty is not more fundamental than difficulty of producing light bulbs by Edison. The thing I do not want to normalize w field by

I would argue that this difficulty is not more fundamental than difficulty of producing light bulbs by Edison. The thing I do not want to normalize w field by its difficulty - then progress would be just related to the effective number of smart people working on it. I was raised in a scientific culture (Central/Eastern Europe), where difficulty was a virtue, not - impact. But that way produces a --lot-- small number (because they are difficult!) of difficult results, with little impact. Likewise, the most progress happens where there are low-hanging fruits.