Mostly because the racism and culture of humans and the chantry or the qunari largely destroy or absorb and then destroy anything that disagrees with their beliefs.
The elves have no culture to call their own outside of the Dalish clans. The City Elves are andrastian, the elves who join the Qun are qunari, and there are no other elves out there besides the Dalish, and the Dalish, while having a largely wrong narrative of their history, is the only group that has it.
You're dodging the question I posed before: are cultures intrensically equal in worth, or not?
If cultures are equal, then voluntary assimilation within one, or willing adherance to one in which you are raised, is not a flaw.
Racially-exclusive cultures have no exceptional merit unless cultures are not equal- that there are better cultures, and worse cultures.
The recent discoveries need to be shared and it'll be up to them to accept it, but until the Chantry and the human nations are willing to be tolerant and let the elves develop a land and culture of their own that is strictly elven, let alone one that does or does not reflect the Dalish beliefs, there will be almost no opportunity for the elves to move forward.
The very racism and religious fervor outside the clans keep them as nomads, and they can barely advance as a result.
Why outside the clans? Why not the very racism and religious fervor inside the clan?
Moreover, why infatalize the Dalish as so? The Dalish prove they do not need land to hold a culture- why do they need one to change it? Are they children
I think the elves in general deserve a land to call their own and the true history of the elves to be taught, but I don't think it needs to be one that has to be built up on the humans own terms, which will be join the chantry and move into an alienage and deal with the racism of humans, or the qunari's which is join the qun or perish or have your mind destroyed and be a minor laborer.
Will this nation of elfyness allow other equally valid cultures to mingle and possibly convert, or will it suppress and seek to expel them to the borders as wrong and/or inferior?
And what is the 'true' history, anyway? That the elves were impotent and victims of their fate? That they were strong and brought tragedy upon themselves? That the conversion to Andrastianism was a horrible crime against elves? That the Dales were the cause of their own fall?