Hi,
This particular discussion occurs a lot and often folks conflate time and place, which is what Rich was referring to. Simple plain jane mountain rifles are from the 19th century. Many of the plain long rifles from other regions, like PA are also from the 19th century when the fashion for carved rifles waned replaced by plain guns or those with lots of metal inlays. There are many carved and decorated colonial, Rev War, and golden age (late 18th and very early 19th centuries) guns that show a lot of use and during those periods some decoration was often applied to even the most humble objects. Why were so many decorated golden age long rifles converted to percussion if they were not being used? A rifle was a major investment and I believe if the owner could afford some decoration to make it distinctive, he asked the gunsmith to include it. I suspect that if someone could afford a more decorated rifle he would dump his plain gun in a heart beat. Look at Davy Crockett's alleged "first gun". Even rifles supplied to native Americans often were decorated. Consider the purported Paxinosa rifle that was discussed in this forum. It is also important to consider that colonial and Rev War period Americans were in general, more prosperous than their European counterparts. Things changed after the war as a series of bad recessions hit the new US. The flood to the frontiers in the 19th century also created a demand for trades allowing gunsmiths both skilled and mediocre to make a living. I believe it was tradition among the skilled and trained makers to do some decorative work regardless. However, as time passed those makers still steeped in European traditions of gun making died off leaving less formally trained makers in their wake. Carving is hard and time consuming, which likely is one reason it mostly disappeared. Metal inlays are quick and easy once you get the hang of it. Engraving is hard but most of the engraving (with some great exceptions) on later long rifles looks very crude and unskilled. Often the metal inlays were left blank. So, in my opinion, discussing plain versus decorated long rifles without context of time and place is not a very useful discussion.
dave