The High elves never built anything atop the moutains of Ulthuan, I understand that they won't live inside because they are not dwarves but why not build settlements or outposts atop them? They have dragons and eagles to reach these quickly if needed and they could have easily defendable positions in case of an attack. So why don't they go up there?
Ulthuan, Home of the Asur. If any high elf player is in the hobby too I would suggest you to check this forum.