Originally Posted by
Vyrerus
Hermes:"And though its existence had long been theorized we had no proof until the flower's serendipitous creation."
This is the important line. While the flower was created on accident, its mechanisms proved a theory that had already been postulated. Like the Hannish theorize about it as Akasa, the Ancients first theorized about it as Dynamis, and the Elpis flowers validated their theory.
By the act of creating them, an understanding of Dynamis was gained. Hermes uses this line and the line prior to explain how they discovered it. The flowers are tangible, and are an accidental prototype for all Entelechies. By studying the accident that lead to their creation a method to manipulate Dynamis was gained.
While it is not a direct line, it is fact based on how more advanced Entelechies, namely Meteion, came to be created on purpose. Then, note the underlined, We, in Hermes' statement. He was not the only one researching the theory, and he was also not the one who achieved the accidental breakthrough.
Again. There are more Ancients than just Hermes who know and understand Dynamis. Explicitly. They just aren't named.