It’s not the large film size by itself. The main reason is camera movement: large format cameras let the lens standard and film plane move independently.

To keep verticals parallel, the photographer keeps the film/sensor plane parallel to the building instead of tilting the whole camera upward. Then they shift the lens upward to include more of the building in the frame. Because the camera isn’t tilted, the vertical lines don’t converge.

Large format systems are especially good at this because their lenses usually project a large image circle, giving more room for shift movements. But the principle is the same on smaller formats: a shift or tilt/shift lens on an SLR or mirrorless camera can do the same thing.

So the effect is mainly due to lens/camera movements and image circle coverage, not something inherently caused by large format alone.