Nokia Lumia 920 Sold out Everywhere! Is that a very happy news or sad news?

There are endless reports of Lumia 920 getting sold out everywhere. Telstra, Clove, AT & T Everywhere.

What makes me wonder is, is this only because, these carriers are stocking very low number of Lumia 920's? I know Telstra and Clove are about online preorders, but I do not understand what's the matter with them getting sold out as well. I mean how can online preorders get sold out.

AFAIK every AT&T store had atleast 400-500 iPhone 5's at launch. But that doesn't seem to be the case with Nokia Lumia 920 at all, with each store having a maximum of 10-12 Lumia's and that too only Black mostly.

Is that normal with any launch other than that of iPhone 5 & Is this the main reason of Nokia Lumia selling out everywhere?

Or is it because, Nokia and every other carrier underestimated the response towards WP8 & Nokia had made very few units available to these carriers?

Or may due to the fact that WP8 is really very popular with sold out posters everywhere?

I personally hope it is the third option. What are your thoughts out of the three?