Series 5, 6 and 7 released really close to each other, I think Moose is taking a break to make other toys at the moment, like the Uglys' Petshop, and Mutant Mania.
Maybe they'll make series 8 some time in the future, there was rumor awhile ago that they were making ideas for series 8 during series 5's release - and we saw the ultra rares in 6 & 7 being similar to 5's special editions, they could still be coming up with ideas. Plus, the cartoon is still going on (I think), so they probably haven't given Trash Pack up yet.
