At the time we are sent to Elpis, within that trip to the past, we were sent to a precise day by the auspices ofthe scriptwriterfate. While we meet Emet-selch and Hythlodaeus, and we know the offices they hold, we know no big details about the duties of said offices nor how long either of them have held those offices. If you've ever been elected, promoted, or placed into a leadership position to fill someone else's shoes, then you would realize that you don't get the 4-1-1 on everything in your domain on day 1. Sometimes not even year 1, depending on the gravity of the office. Then there's also the fact that in a lot of jobs, leadership position or otherwise, there's a lot to the job but there are operations and necessities that are so infrequent as to be forgotten. Even by veterans. Compare and contrast with a submarine captain. The captain has to know every system of the boat in a general sense, but has to delegate specific responsibilities to lower officers who then carry out actually working everything with their different divisions. Hythlodaeus could be the most competent Chief of the Bureau of the Architect that the Amaurotines ever had, and he probably still wouldn't know the skinny on each every creation ever submitted. It's a huge operation.
Mmm, don't misunderstand me. I do not mean it is an emotional conflation for Emet-selch. I meant it is one for the player. "Wow he doesn't know, I'm shocked! This must be a really mysterious force." Something in that vein. But as we see in this portion of the MSQ, the Convocation don't even work together. Later on in Pandaemonium we get even more of a suggestion that they are akin to the Sharlayan Forum, and they don't work together till they call a meeting to do just that. It still makes sense that no one told Emet, because Dynamis does not pertain to any of the Convocation's jobs at this point in time. Serves him right too, just standing there not calling up Grani or anything, monologuing into memory erasure. SMH
I'll point out, as you have pointed out, Hermes is the leader of Elpis. Leaders often abuse positions of authority to bend and break rules. Subordinates do not call them out for fear of loss of position or loss of potential increase in rank or pay. It's not really a commentary on how lax rules are in Elpis, but moreso that Hermes is beholden to no one there. There is no one who can, or wishes to, enforce the rules on him.
Also, I'll state that it is merely plot contrivance that the researchers are kept obscure. Like I said earlier, it would have been better if the lines were written to be that Dynamis was Hermes' personal discovery without mentioning anyone else. However vaguely they were mentioned. If I'm supposed to embrace the vagaries of Venat/Hydaelyn retroactively, then I am going to embrace the vagaries about other segments of the plot too. And if they are spiny and shifty and questionable, then I will question them and point them out. This is the case here. Hermes is not the only Ancient well versed in Dynamis.