^ There is no way the Sphere Builders could rebuild the expanse to cover 1/4 of the galaxy like in the Ent-J timeline. That version of history assumed that work on the expanse began prior to ENT, and lasted continuously for 400+ years. Even if the Sphere Builders started over, as of the 24th century, it would take much longer for them to get it done.
(Assuming the Sphere Builders even survived the events of Zero Hour - which is hardly conclusive.)
Besides, now that it is widely known how to destroy the spheres, they wouldn't dare try again anyway.