the choice facing neuroscientists in the early 20th century: study the cell that seemed on the verge of yielding all the secrets of the human mind, or tell your advisor you wanted to study glue instead.

Very plausible! But I would also like to know how this stable state eventually got upset. Who were the first people to study glial cells? Did they have any distinctive characteristics (personality/educational background/institutional affiliation/...) or did anything in particular happen that prompted them to take an interest in glue? It seems that if we could replicate that miracle, it could be very beneficial for science.