But before stating that intent, he admits "well, that parable didn't work". The strongest interpretation of which is that the parable he wrote didn't succeed in being about "the dangers of becoming too powerful".
We have to read "was about" as "was (supposed to be) about".
What the parable ends up being about is any consistent interpretation well supported by the actual text of the parable!
In the parable, the Whispering Earring is a kind of character. It has autonomy and agency; a mind of its own, separate from that of the wearer. It generates ideas and suggests them to the wearer, eventually rendering most of their brain unnecessary. (The implication being that the individual, as a sentient being, has wasted away and has been effectively replaced by the host, as if possessed in the classical sense).
Someone who could be just as powerful in making all the right decisions guaranteed to make them happy, but using their own brain instead of taking suggestions from a whispering daemonic oracle, would not waste away and be replaced; their brain would have to be doing remarkable work and developing in the process rather than atrophying.
I suspect that it would actually be very difficult to repair the parable, while retaining the key element of the Whispering Earring as an autonomous entity, into being about "the dangers of becoming too powerful oneself". (Has the author tried?)