how durin founded the longbeards

[mhagain]

Originally Posted by Inziladun

Then again, couldn't one say the same of the Elves' awakening at Cuiviénen?

Of course it could; the Cuivienyarna is presented as a mathematical lesson, after all:

Actually written (in style and simple notions) to be a surviving Elvish "fairytale" or child's tale, mingled with counting-lore.

That said, the Elves do have survivors from that time still among them (Círdan being a notable and likely example) whereas the Dwarves don't. You'll notice that Tolkien is careful to qualify statements about the Dwarves with "it is said", "it is told", etc, so even within the framework of his own stories it's being presented as a legend.