I love the movie far more than it is reasonable. I watch it when I just can't cope with the universe anymore. But I watch it because it's awful, it's silly and it's a lot of great actors having entirely too much fun.

Damien Lewis doesn't hurt either, and his accent is...fun.
I just don't think it took the world by storm in the way that the all-star cast and the style of promotion seemed to think it would. It landed with a resoundin 'phut'.
A series of these movies, each with a decreasing budget -thus changing cast, each with an increasingly inappropriately aged Alex Pettyfer or with an disconcerting series of alternatives, would just ruin it. The books also do get increasingly adult in their violence, so really, Missi Pyle wiggling her legs in the air under a jelly fish=comical, a man gradually being stoned to death by quarters? Not so.
That said, if someone wanted to get grown up Alex Pettyfer to wear the slaveboy costume from Scorpia, you would have yourselves a pretty big built in audience right there.