These remarks seem oriented towards a style of play which is (in a broad sense) puzzle/mystery solving - CoC adventures can be like that, where if you don't solve the puzzle then you lose the adventure (in the sense that you can't continue) - or, alternatively, which is about playing through the pre-established story.
I hazard a guess that is how most DMs (including me) run their adventures (the second option). Certainly MiBG (Murder in Baldur's Gate) and LoftCS (Legacy of the Crystal Shard) were designed that way.
The other is "indie"/"story now" style - where the significance of the map being hidden isn't because it is a puzzle-solving challenge, nor because it is a clue to get from A to B, but because something in the dramatic essence of the situation or the characters calls for a hidden map. If the map is discovered (eg by a successful Scavenging or Perception check) then that particular dramatic need is satisied, and things unfold one way. If the map is not discovered (eg because a player never finds his/her PC in a fictional context that allows the framing of a check to find it; or because a check is made but fails) then that dramatic need is frustrated, and the resulting complications lead to things unfolding a different way.
This echoes my preferred game play. Secret backstory in our table's lycanthrope storyline being that The Hound was a beloved mentor of one of the PCs. He (player) missed all the story-line clues, only to eventually have The Hound reveal himself when the party made themselves too troublesome for him to continue to ignore them and so confronted them revealing his nature. That was GM pre-authorship added onto player derived background. I suppose this could have been developed at the table but I wouldn't know where to begin. By doing it my way I was able to frame clues properly and set-up well-thought out situations and so when the big reveal occurred (4 years of RL game-time) the player loved it.
He could have solved it earlier and that would have been perfectly fine too.
EDIT: I'm just glad as DM the campaign never ended before I could spring the surprise twist - that their arch enemy was a dear friend and mentor.
The peddler, the feather, the tower and the dishevelled figure were authored by me as GM - they were elements of framing.
I'm not interested in arguing the meaing of words - that's a tedious pastime that I'll leave to the pedants.
I'm interested in discussing a particular pheneomnon in RPGing - namely, GM pre-authorship of setting. If you don't think "worldbuilding" is an apt label for that, fine - in your imagination substitute some other term into the title of the thread.
Well, I think that is the issue - the meaning of words - where you seem to differentiate between framing and worldbuilding.
Framing a scene can (usually does if not always) lead to worldbuilding.
A tower has been established through the framing - a tower that wasn't there before. I don't know how you can't see it. I believe this is where everyone is having the disconnect with you.