There is an RPG called "Bubble Gumshoe" where they make the same point that you do that mysteries with clues should always be able to be found otherwise things would grind to a halt. The solution used by Bubble Gumshoe is that failed roles cost a resource not that the clue isn't given. So in D&D maybe failed roles cause exhaustion, gold, HP, or some other resource (depending on circumstance).
There is an RPG called "Bubble Gumshoe" where they make the same point that you do that mysteries with clues should always be able to be found otherwise things would grind to a halt. The solution used by Bubble Gumshoe is that failed roles cost a resource not that the clue isn't given. So in D&D maybe failed roles cause exhaustion, gold, HP, or some other resource (depending on circumstance).
Some interesting might-have-beens from those early plot ideas!
If the roll doesn't matter, don't make them roll.