The whole point to the major RNG factor with this, is to prevent people from progressing too fast, kinda like the reason for coil lockouts and the soldiery cap. That's why they didn't increase the drop rate for 2.3. Likely, that increase will come in 2.4 (my guess).
Before they said they wouldn't touch the drop rate, they said they would examine player feedback concerning it. Player feedback, of course, includes the data of what people are doing and have done in the game. That's what I meant before when I said SE has the data. The fact that they are not increasing the drop rate yet, simply means that enough or more people than expected are seeing this content through and are making progression. We will likely see an increase in the Atma drop rate, and a cheaper Myth price on the books for 2.4; along with the release of BCoB3 and the Echo applied to BCoB2 (again, my guess).
Also, they already have stuff gated behind harder content, it's the High Allagan weapon (which is still better than the Novus).
Mind you, while I don't agree with the grievance, I do understand what you're saying. So I don't want you to get the idea that I'm trying to argue or that I have something against you, in case I ever came off as such.
EDIT:
Do you understand how probability works?