As you may know, The Twilight Zone (no, not X-Files) Tower of Terror at Disney’s Hollywood Studios has been undergoing a refurbishment for the past few months. Instead of closing down the entire attraction, Disney opted to approach the refurb in phases, although that still meant reducing the ride’s capacity over the span of a few months.
The refurbishment began back in early Spring 2019, alternating between different ride shafts, leading to longer wait times throughout the spring and summer months. To mitigate the ride’s lessened capacity, fewer FastPasses were distributed for the attraction. (Which is probably why you couldn’t get one even weeks out at some points.)
The right elevator shaft was finished first, and the left shaft has since been closed again. However, there are no walls in the queue since work on the attraction will be done any day now.
Soon, the Tower will be back up and running to its usual, (para)normal capacity, ideally with all of the show effects fully functioning. With the opening of Star Wars: Galaxy’s Edge, the park will need as many E-tickets as it can to mitigate the crowds flooding into Batuu.