They bear no resemblance to any Elven art or architecture I have ever seen, nor have scholars I am familiar with every connected it to ancient elves. The pyramids are like nothing else in Thedas; mathematically near-perfect despite that they must have lacked modern tools of construction. I've published a paper on the subject, if you would care to read it. Visitors from far across the sea is a favorite theory -- quite literally outlandish. [ get it haha academic humor ]

As for their docility, I think not. They have no sophisticated tools or learning, no evidence of written language, and so forth. I suspect more likely that they were a small community isolated from society for so long that they became insular and some plague or similar disaster was able to wipe out much of their cultural knowledge and cause them to revert to an earlier time.