Huh.
See, when I look up
the year 1486, the year I gave for the near-conquest of the country, the wiki says to me that "The Shadovar besieges Arabel and Suzail until Nightal 1 when both sieges are broken and many shadovar fall."
That's only two of the three big cities of Cormyr, and I said "literally all", so if we look up the third,
Marsember, what do we get?
"When Cormyr was invaded by the returned empire of Netheril, in the Year of the Nether Mountain Scrolls, 1486 DR, Marsember faced peril once again. The city had to be abandoned for a third time, as its citizens evacuated its walls from the invasion of the Shadovar."
Hmm.
It looks like there was, in fact, a "forced evacuation or siege of literally all its major cities three years prior to the 'present day' of the
Sword Coast Adventurer's Guide."
Yes, it does. And it mentions the exact events I described, in the exact year I gave.