There is some 1930s bell labs paper on coaxial cables that considered available materials and concluded 30 ohms was best for power handling, 77 ohms was best for low loss, and 50 ohms was selected as a manufacturable compromise. The publication I'm thinking of would have been by Espenschied most likely.

Edit: ah, I see the fine article also says this-- in any case the name might be helpful to someone looking up the citation.