Wasnt that revealed a long time ago? that the towers show up on soon-to-be destroyed worlds in order to serve as an arc to preserve a small portion of it?
Treasure often falls into the hands of those who do not know its worth.
only the people on way higher floor where the only human aware of it is park, and he cannot leave the 99th floor since he never used the gate to reach that floor, he can only leave the floor during his administrator quests, and even then , he is stuck in the area of the quests
so no one outside the tower knows about that