I think the reason for writer’s block is when the complexity of the plot of the story (or the architecture if the software you’re writing, or...) becomes too great. To write another page it’s not enough to just come up with some new ideas. Whatever you write must simultaneously satisfy the existing strands of the story, obeying their internal logic while tying it all together. If the writer has a strong philosophical core to their work, then this could halt output all together rather than just for one individual story (because their whole output is really a continual development of their philosophy).