I'd speculate that the increase in string gauges probably started when mandolins were unpopular and proper mandolin strings difficult to find. #Some probably used whatever guitar strings were around, which would make it difficult to find E strings any smaller than .011. #Somebody put such strings on a bowlback and wrecked it, but somebody else put them on a Gibson and decided it sounds better than it ever did with "proper mandolin strings" of the day.
As I said in another thread a few weeks ago:
There's a definite historical trend towards louder instruments, at least in Western culture. #It's been going on since at least the Baroque and even the development of amplification hasn't stopped it. #It's an arms race, and its history and causes surely make a fascinating subject for various scholarly types.
Mandolin players might be affected by this less than trumpet players and very few of us need maximum projection (unlike those poor bluegrassers who have to deal with overzealous bluegrass banjos) but I think classical mandolin design is driven by high-end models whose prospective buyers need to keep up with grand pianos louder than those of yesteryear. #And so it goes...
Yeah, I sometimes wish drummers would go back to using skin heads and horn sections would have to play quietly so an unmiked vocalist can be heard over them, but on the other hand I do play every week in a large church with lousy acoustics and it's nice to be able to do it unamplified.
Peter Klima (not the hockey player)