Mainstream game design has moved toward minimizing these down times, adding mechanics like fast travel or quest markers to get players straight to the next point of interest, another filing away of the adventure game’s rough corners.
I think the lack of fast travel in Walking Simulators forces players to think more about the environment around them. This function reminds of Red Dead Redemption where for the early part of the game the player is forced to move through a large world on horseback. The lack of fast travel forces the player to explore the wild west and take time to see the environment around them. Walking Simulators believe in this experience as well as investigating every part of the environment is how players learn more about the games narrative.