This is described in The Law of One as Service to Self, as opposed to Service to Others. According to Ra, they have never witnessed the ascension of any beings on the Service to Self path to higher than 5th density (I think it was 5th, open to fact-checking here), nor could they even understand how it was possible.
If you want to walk this path, you cannot do it casually - this is Genghis Khan, Hitler, Stalin, & Chairman Mao level selfishness. It’s a path of strife, contention, & pain in a continual struggle to be the one on top, all to eventually get to what seems to be a dead-end in the ascension path.