The correct answer to this open question is the following.
The development from the period 1861 to 1865 that was not directly mentioned in the excerpts that support McPherson's argument is that the perspective or point of view of James. M. McPherson considered that the way of living in the South was transformed as well as its institutions due to the presence of the idiosyncrasy of the North.
We are referring to a part of the work of historian James M. McPherson, reflected in "A War that Never Goes Away."
In one of the excerpts, he wrote: "...The Civil War was a total war in three senses: It mobilized the total human and material resources of both sides; it ended not in a negotiated peace but in total victory by one side and unconditional surrender by the other; it destroyed the economy and social system of the loser and established those of the winner as the norm for the future..."