What purpose did the isle Azys La serve? Main Storyline Spoiler.

[hagare]

Some parts of the Lore and MSQ are confusing or not clear to me. The Azys La structure seem monumental and phenomenal. How can a civilization so advanced disappear without a trace. They could remain on Azys La and survive. If Azys La is intact it means the people on it could survive too just like the mobs living there. That place is just weird as it is. It looks so alien ish. That warring triad is a mystery. Are they the source of power that fuels the whole place? If they break free / die or whatever won't make the whole place fall down destroying it? Or it just a huge magical experimental flying lab / Alcatraz of some sort?

consider the real world.
with so many nukes flying around to destroy the world more than once.
disappearing civilization doesn't seem so unlikely now does it.

[Colorful]

consider the real world.
with so many nukes flying around to destroy the world more than once.
disappearing civilization doesn't seem so unlikely now does it.

When the ones who are making the nukes are the ones destroyed, it starts to make less sense. For none of them to survive too? It's just that "Oh, there was once an ancient and great civilization here that are far more advanced than even people thousands of years ahead of them, but now they're gone" cliche. It's been used so many times in so many forms of media that I've grown a distaste for it.