So it seems as if it was the True Immortals and Gods who initiated the era of Chaos Void expansion, but the true backbone of this movement were those Spirit Realm cultivators. They are the ones who can truly delve into a world and bring all the resources back to the Divine Land World.
Perhaps once a world's coordinates are obtained, building a corresponding Guiding Altar can guide the strong from the Divine Land World to descend. However, the costs involved are innumerable.
Not to mention the resources required to construct a Guiding Altar in a world, even for a large immortal sect, the cost is formidable. It might be acceptable to establish Guiding Altars in one or two important strategic worlds, but establishing a Guiding Altar in every world isn't feasible.
Some worlds are destined not to be operated in the long term. Their significance lies in short-term harvesting, and then they are merged into the Divine Land World. Building a Guiding Altar at this point would be a loss.
