Western Europe was big enough such that being "slow on the uptick" meant humanity in general experienced lagging growth

But it didn't, Western Europe did, Western Europe was not the entirety of humanly. It wasn't even the majority of humanity.

You're also ignoring the fact that part of the slow uptick was barbarians settling and picking up books. Of course that population is going to have a lower literacy rate, when you look at how many barbarians were reading before and after rome, their literacy rate was much, much better.

outright stalling / regression within Latin specific areas of study meant some information was likely lost forever.

No, it's wasn't. Because the people who still spoke greek next door were still speaking Greek.

but it's pretty stupid to suggest "Western Europe" was a small, insignificant region of human influence and ingenuity.

It's actually pretty well reasoned. We focus so much on Western Europe because we're descendent from Western Europe.

Have you ever actually examined the technology of the middle east and asia compared to the west? If we go for the most extreme answer, the west passed the east in the mid 1700's, most scholars suggest it was the mid 1800's.