What's the point with that quite lackluster story in Endwalker?

[Absimiliard]

That's nice and all but the reason I even brought it up is because originally either you or someone else (probably both) were still in the "lol ancients casually do this" phase. The post a few pages back you all liked. Thr goalpost has moved since then and we now agree it's not so common. Aether changing up has nothing to do with it-- it didn't occur to Emet because the past viewing thing is particular to Venat and whoever she teaches it to. We have known this for several expansions yet I still see it commonly thrown around as though it is true. It's not. The Echo is a general gift with a diverse array of applications depending on the user and their interest /aptitude.

A good deal of what you've said here directly contradicts information put forward in the game and its peripheral materials. Firstly, being able to gaze into the past has at no point been associated solely with Venat, save perhaps early in ARR when it was still believed the Echo was something she gave people. What we have seen over the years is a number of characters - some associated with Venat, some not - utilizing this ability, some of them with far more control than the WoL or Krile have ever displayed. I might also note the subject of this ability is discussed by her in Elpis, and at no point does she remotely imply it's something unique to her. Furthermore, you are once again disregarding the fact ancients did not, unlike their modern fragments, suffer from involuntary activation of their powers. Any situation wherein Venat or any other ancient sought to look into the past was explicitly stated and even shown to be something they had to do willfully.

Oh, and no, I didn't claim every ancient could do it, although I did point out two things; most plot relevant characters with the Echo have at some point been shown into the past or otherwise reading aether in various ways, and the other being the fact the game rather strongly implies it's nothing special amongst the ancients.

Venat telling us she isn't going to cause people to panic is not equivalent to being told she did nothing. Please stop trolling.

We're told quite explicitly she didn't interfere with the summoning. Please stop trolling.

Emet straight up says they didn't have the technology. I don't know what to tell you.

Pretty sure I'm going to take the data stored in an ancient database over the word of a guy that didn't preside over the sciences.

Except the cause is Hermes so telling Hermes doesn't seem helpful. Secondly dynamis was an emerging thing at the time. So they were handicapped on those two points alone really. Either way Venat telling everyone everything, even if she did, is not really an argument for fixing Endwalker or averting the final days. It may have changed slight details but the outcome would be the same.

Hermes was not the entire Convocation of Fourteen. He was an individual member. What's more, he was far from the only person in their society studying dynamis. Similarly, he was far from his society's foremost expert on creation - that was Lahabrea. Both toiled to bring forth Zodiark, but their knowledge of the true source of the Final Days limited them to creating a temporary, albeit extremely long-lasting, solution. Plus it got them tempered. Y'know what might've been helpful? If Venat at least bothered to warn them about tempering, because they did not know it was coming.

The sundered Zodiark protected Etheirys and its shards for 12,000+ years and showed no signs of weakening in all that time. I don't know about you, but I find it unreasonable to just assume a society as enlightened as that of the ancients wouldn't have been able to develop a more permanent solution to their problem in that time if given information as to the actual cause of the Final Days. To make the assumption they were so incompetent is to disregard every shred of lore we have about them, their capabilities, their sciences, and their civilization as a whole.

And to your last point; Venat retained her agency in the paradox. The story makes it quite clear she was free to end it by simply choosing another path, but she elected not to. Rather than picking the unknown, she chose the one future she knew of where the world and its inhabitants still existed in some form. She took this course in large part because she lacked faith in her people.