Sacrosanct
Legend
While interesting, I see three assumptions here that do not seem well grounded:
1. The war band of folks with varied skills has ever gone out of style
2. People have ever stopped believing in "magic" (however that is defined)
3. At some point people started believing in "science" (however that is defined)
1. War band out of style? No. But with members of that band having clearly distinctive archetypes (intellectual who avoids physical combat, warrior, rogue)? I don't see much of that during the Romance age up to the Industrial Revolution. I see a lot of lone fantasy heroes, or where the group is pretty much all the same archetype with only minor difference in skills (mostly different in personality)
2. I'm talking about majority of the population. I think we can trace this to the rise of Christianity in various locations as to be able to trace the shift. It seems the belief in the supernatural and magic is/was more prevalent in polytheism as opposed to monotheism.
3. I think this is really at the tail end of the industrial revolution when science became the widely accepted norm. Especially the 19th century. We can definitely see the rise of science in fantasy writings during that time period. Mary Shelly, Verne, HG Wells, etc.