I agree that prescriptivism taken too far is counter-productive and damaging, but must argue that having no agreed rules would be an even more serious state of affairs. We’d have chaos. I quite often have to ask people to re-phrase what they have just said so that I can understand what they really mean.

The grammarians seem to take even more liberties with the English language than teens do. The different (and conflicting) definitions given for the term ‘absolute adjective’ is one example, as you point out.

I’d rather like the Wiktionary definition to be standardised – an accepted use of adjectives in a position (in commonly-used structures) other than attributive, predicative or postpositive.

Most authorities would not agree with you that “adjective phrases . . . are consistently placed [immediately] after the noun they modify (in English). Here are some valid counter-examples:

The very hot blue stars are extremely luminous.
It was cold, bleak, biting weather. (Nordquist)
Messi is a very, very talented footballer.

And, tweaking the parenthetical adjective phrase from Wikipedia:
“Happy with his lollipop, the boy did not look where he was going.”

Edwin Ashworth