There were only two minor mistakes. First, Daniel Morgan did not lead the First Pennsylvania Infantry. He was only a captain in it. Second, W. W. Greener was the first inventor of the expanding bullet. Other than these trivial points, the author has a very well researched and written article.
We must be reading a different article.
The rifle was not referred to as a Tennessee nor Kentucky Rifle until after the AWI
The British during the AWI normally fought at "open order", from the beginning, meaning with a space of one arm length between the files of the men.
"Platoons" were not used. Company fire was the most commonly encountered method. Companies could be organized as 50 or 100 men, ..., one will note that Morgan had 96 men in his "company" when he departed VA.
At the beginning the normal British tactic was to jog, at open order, at the Continental Soldiers, who would fire at too far a range (100 yards) and by the time the poorly trained Continentals had reloaded, the British had arrived with bayonets...something the Continentals lacked for the first few years. Until Von Steuben, they didn't slug it out with volleys vs. the Brits.
Soldiers did not normally drop the ball down the barrel of the musket onto the powder, but rammed the ball wrapped in paper down to the powder charge. Since the balls were smaller to allow for fouling, the ball was never centered in the bore in a consistent basis, thus the inaccuracy. Musket balls didn't rattle down the bore when loading. A bare ball without the powder has a tendency to roll forward when the private snaps his firelock into the position level with the ground, and a space would have been formed blowing up his musket upon firing.
British infantry with their muskets were trained to fire "at marks". Granted not nearly as accurate as a rifle, nor with the range, but they didn't just point and pull the trigger. In fact in the F&I in North America, The Company of Select [musket] Marksmen was formed, and could consistently hit a man aimed at, at 90 yards.
The problem with the rifle was NOT complication. The problem with the rifle was the lack of a bayonet AND it's need to be thoroughly swabbed about every third shot. It ceased to be a weapon in the rain, while the musket was a spear that could also shoot, and shoot a lot without needing to be cleaned in the middle of a fight.
See
With Zeal and Bayonets Only by Matthew Spring
and
System for the Complete Interior Management and Oeconomy of a Battalion of Infantry by Cuthbertson
LD