Precisely why is this hard to square away?

If the measured cognitive abilities of a typical 2000-era Homo sapiens are statistically significantly different from 1900-era Homo sapiens, to me that casts some doubt as to how likely similar a 125K years ago and since out-competed species was.

Was the era from 1900 to 2000 so special/different as to be a one-off?

(This is obviously an unpopular line of inquiry/source of confusion based on the voting.)

For one literacy right now is ~100% and has never been anywhere close to that until 50-60 years ago.