Remember that Ralph Page started calling in the 1930s, and became a full time caller in 1938. If he called dances all the way through, it's because he was used to doing things that way from the days before sound reinforcement at dances (and remember that he probably called three squares between contra dances!)
Here are some quotes from Page's 1937 book:
A good caller's "voice ... must be clear and distinct (not necessarily deep in tone) and must penetrate the farthest corners of the hall."
"The best prompters baby their throats as if they were opera singers. Their greatest horror is laryngitis. They don't drink olive oil or wrap up in pink cotton batting, though; strange as it may seem, the oftener they call, the better their voice. They claim that six nights a week are better than one or two, because their vocal cords are really exercised then and so become stronger."
So it sounds like Ralph Page, and the other callers of his generation, didn't believe in trying to "save" their voices.
Jacob Bloom