Because Incarna is not an official company or commercial effort (as of the writing of this), many pieces of content get published that would not be considered ‘complete’ by commercial publishers. This is done sometimes to just reduce the workload, other times because a particular piece of the story was an aside, or not crucial to the campaign or setting it belongs to. Presentation of the content can range from barely presentable as a basic idea/concept to complete and publishable.
LOTS OF TEDIOUS COPY/PASTE. AUGH. UNFINISHED.
While many designers, testers, and contributors worked on it over the years, only Kelly Berger published it. This makes it difficult to focus on the mechanics and world/adventure content. Adopted 5e mechanics and focus on world building and adventure writing now, along with a set of home brew rules that adopt the best of the old Incarna 5.0 concepts to the d20 system.