Would just like to point out that Vaclov Smil says the time period between about 1870-1910 is unmatched by any other time period before or since, excepting a sliver of the Han dynasty, as measured by the rapid surge in invention, innovation, and the rapidity with which those new ideas were employed in the broader society (rate of adoption). He goes on to say that even in today’s seemingly endless cycle of new products and legitimate advancement, we’re making only point solutions in comparison. For instance, the whole-house AC power system would be easily recognizable by Edison today. Improved, yes, but compared to going from nothing to the direct-to-home and whole-home solution set, it’s illustrative of relative stagnation. To be clear though, he said that it’s unrealistic to expect society to perpetuate those periods, as they are flukes - again, only twice in recorded history. I’m not doing the depth of his reasoning justice by any means, but I think his would bring another interesting angle to the idea that you relate from Russell.