that's a great post/article by rich pierce, thanx for sharing billingsdave!
all of what he laid out is pretty much the way i see it with concern to rifles, and smoothbores, and both the settlement and conflict periods of the 18th century. there *probably* just weren't that many rifles around, and super rarely for warfare. even washington decreed his army sport no rifles, muskets only. and for excellent reasons!
it makes absolute sense for non-military folks to have a smoothbore as well, as it's the perfect tool for fowl or game, particularly on the coast side of the country were fowl was probably (and eventually) more plentiful than small to deer sized game, and forested areas were thick. in the nor'east game populations were decimated as the indians used hides to acquire firearms. i've read where the natives preferred rifled barrels for the taking of deer at longer ranges simply because deer had been way over harvested in their quest for skins.
however, reading the further into the thoughts and theories of others, whilst the coastal settlers preferred smoothbores and the natives rifles, the "frontier" (up to and past the kentucky geographic areas) longhunters preferred rifles, perhaps in more open land areas, most of which (within those settlement and conflict periods), were shorter barrelled and far more of jaeger design origins. whereas the "american long rifle" was more of a design that grew during the rev war, and really blossomed post rev war during the "golden age" of the american long rifle.
so ... perhaps it might go like this - during the early 18th century (1725-1770) smoothbores absolutely ruled for everything and rifles didn't look much like golden age american rifles, as they were more jaeger-like. reading further, the concept of the long barreled (42"+) could have been spurred on by native americans as they were used to the long barrels of their early "trade" muskets and fowlers, had a penchant for those barrel lengths, and both colonial and british gunsmiths accommodated that desire ... which eventually transferred over to the colonists, since numbers of them took to the indian ways, and therefore the long rifles.