That simple example utterly destroys your thesis. If the player cannot find the key, the story grinds to a halt. The player can blunder around the setting for an hour searching for the key to the locked door, an hour in which absolutely nothing happens in the story. The pacing has been slammed into the dirt. And that’s the normal experience of playing a text game.
Pacing is the manner in which and the speed with which the story advances. When the story does not advance, the pacing has been destroyed. And in a parser game the author cannot control the player’s experience of the forward movement of the story.