Equestria Girls Minis: high demand or slow manufacturing?

[badbob001 5]

I'm considering collecting some of the EG Minis, especially the original single-pack ones, but most retailers don't have them in stock and online prices are at least 2-3 times normals. I've heard that these toys break easily and that probably results in more returns.

 

So is the low inventory due to Hasbro selling off existing inventories and then either abandoning the old sets or retooling the design / process? Or is it that the manufacturing can't keep up the high demand from collectors, who don't worry about breakage since they won't play with them much or may not even open the packaging?