Of course, the lack of rigid requirements is also a reason; they can only connect to the Fictional Universe, because this is a Fantasy World, and things from the outside can't enter the reality of the Sixth Era. That's the real "reality reason".
In the mobilized forces, even the Blank God is helping them.
Those lost histories have already been edited into books by the Blank God and thrown back into their world's libraries. Countless scholars are working day and night, trying to research something from history and lost technology, while also contemplating how to use the various technologies transmitted back from the Sixth Era.
The broken worlds cannot reach the Stellaris because the Stellaris have also shattered.
Those worlds are merely gardens molded by the Blank God's hand.
