"I'm the first person to own a dungeon, I don't know if other aspirants have access to dungeon cores just I do, but mine is unique. Anybody, well any normal person taken into the dungeon would develop access to the system and would be able to travel through and fro to a location in the system universe.
Of course that location happens to be my own territory, and the dungeon is calibrated to our reality's own interpretation of the system. As I'm sure many other aspirants would have found out by now, once you get to level 100 or the integration is complete the system will change. It would adopt a format that is unique to our universe, but would at least share some similarities with the rest of the wider universe.