i really dont think it could .. if you pick a few random users and check their rating curves on lichess it doesnt take long to see that for many, their best rating was at some point in the past. i think this is because their interest in chess wanes over time and they lose rating rather than because their intelligence is decreasing.

i think users that fixate on chess as an intelligence test risk misattributing their performance to their capacity because they do not understand all the factors of performance.