The goal was interdisciplinary because that's how teachers have to teach these days. They don't have enough time to teach each subject separately so they mix things together.
But it would be relatively straight-forward (not easy) to build weekly story-based content that contained geography, history, science, politics, and more. Textfyre was going to align our stories to Common Core Standards. This would have allowed for stable content delivered to all fifty states. The platform also would have had embedded testing. When you complete a story, you've passed the test!
Despite what many people have claimed, Common Core Standards are just measurements http://www.corestandards.org/, NOT content itself - don't get me started on the confusion people have brought to the education world by attributing content publishing to Common Core. The funky math is just a different way of doing math. It has nothing to do with Common Core itself. The real argument is that some states/parents don't want their kids measured nationally. "My Timmy in Texas can't possibly be compared to your Joey in California! They're different worlds!"
We potentially could have replaced several textbooks between 3rd and 8th grade, significantly reducing educational costs and improving outcomes. The crux of the plan is that it needs millions of dollars to prove the model. We needed to develop a proven and approved 36 week set of stories that aligned with existing teaching methodologies, train teachers, develop the platform, security, etc. No small thing.