Boo.
It kind of seemed like WotC never quite knew what to do with it.
As others have said, I can't be too surprised given the weird shifts in marketing the line has taken over the last two or three years. You assume it's not selling, but you wonder at the chicken or egg question - did the move out of big box stores, move from Hasbro to WotC, re-branding to D&D - cause the lack of sales, or were they the effect of lack of sales?
And while the Marvel ship sailed long, long ago, further super hero expansion packs would have been so cool.