The porters, not being blind could see it coming too. As horses became more common in the colonies, packhorses supplanted porters. As with most displaced workers or workers made obsolete by technology, porters extended their anger beyond the horses to the hostlers and to the managers who hired the hostlers and the owners that paid the hostlers. Anybody involved in the changing English trade matrix became a target.
By the middle of the 17th century there was a rapidly growing population of former indentured servants crowding on to the frontier. Virginia put former indentures on the frontier after the Second Powhatan War as a barrier. They were effective in that role but, owing to bad roads and the remoteness of markets, these new frontier folk had very limited prospect of advancing economically beyond subsistence farming. Some became "ponyboys" and scoured the woods of the southeast for herds of mustangs for sale in the coastal regions where they were worth enouugh to make an enterprising and desperate young man a grub stake. Naturally enough, some frontier folk turned to trading with Native American neighbors quite in defiance of official colonial monopolies. Informal, local trade quickly grew into more formal commerce but with a difference. The frontier folk were able to beat the monopolists prices by carrying cargo in and out of the backcountry on horseback thus doing away with the cost of portering.
Something similar happened when wagons replaced packhorses. It is likely, given labor cost in a labor short country, that traders sought the cheapest hostelers possible to run their horse trains. The hostelers would need to be seasoned frontier folk accustomed to moving far away from the settlements and uncomplaining under the most arduous conditions. So, former porters, pony boys, and failed independent traders probably were the hired hands that ran packhorse trains of over a hundred horses (reported by William Byrd II) that carried trade goods in to and hides, herbs, and crafts out of the backcountry. Their hayday lasted from 1676 until the beginning of the second quarter of the 18th century.
William Byrd II, in his History of the Dividing Line, besides telling us that there were packhorse trains of over a hundred horses, incidentally told us that they were no longer using their preferred route across Moniseep Ford over the Roanoke River (about a mile downstream from modern Interstate 85). This may mean that packhorse trade had shifted westward or could mean that packhorse trading was on the wane, and probably meant both. The Tuscarora War (1712-1715) probably destroyed the trade partners closest to Moniseep Ford forcing traders to concentrate on trade with the Catawba and Cherokee. But road orders in Brunswick County, VA indicated that wagons were already crossing the Roanoke by the late 1720s too; packhorses were being put out of business by a more efficient technology.
A horse may carry a couple of hundred pounds of goods, but a horse or ox pulling a wagon can draw hundreds of pounds down the road. Teams of horses or oxen were even more efficient and were able to carry a thousand pounds or more per draft animal. But a wagon needs a road, so the advent of wagon travel says even more about social and economic conditions than it does about transportation technology. But more on that later. Suffice for now that packhorsement wrecked wagons and killed wagoners with great relish when first that technology breeched the frontier.