The high echelons of the Heaven Cocoon Clan had already sent away a batch of elites, scattering and settling them to preserve their bloodline. That alone made a resurgence exceedingly difficult.
The Heaven Cocoon Clan had too many members; it was simply impossible for them to migrate as a whole. Even if they were to migrate, where could they go?
In places where cultivation resources were scarce, the Heaven Cocoon Clan couldn't even maintain their current state, let alone grow and expand. In places abundant with cultivation resources, competition was fierce. Should the Heaven Cocoon Clan move there, they would have to engage in major conflicts with other forces, and the Human Clan might not let them off the hook.
The upper echelon of the Heaven Cocoon Clan hoped that the majority of their people would stay in the Green Lotus Continent to preserve their heritage, while a portion of their elites would leave the continent in hopes of having new Great Vehicle Cultivators emerge.