I'd probably attribute it to retailers already being stuck with generally at least two lines on the shelves, if not more (DOTM, leftover Generations, RTS, PCC). And most still have a lot of DOTM product that isn't moving that well, compared to previous movie lines.

I doubt there was enough retailer interest in adding yet another line (new SKU's, more peg/shelf space etc) to warrant them, at this time.