I overstated my case. Sorry about that. It’s absolutely true that a puzzleless game can be written in Inform or any other parser system. The only valid commands might be the compass directions, LOOK, and EXAMINE. It would be a parser game, or at least a parser story.
The only point I was aiming at, however ineptly, is that the moment you introduce a puzzle, you (the author) start to lose control of the reader/player’s experience of the pacing. You can’t control whether the puzzle is as easy as you think it is, or whether the reader/player finds it baffling and is stuck. Being stuck (which happens to me a LOT when I play games) reduces the speed of the pacing to near zero. That’s all I was saying.