The first sequel may do well if the newer 3D technology Cameron is using piques enough curiosity out of the movie going public.
The other three will do much, much less in cascading dwindling box office here in the states.
The Hollywierd Left will love them and push them as an indictment on the whole of America's existence, but the moviegoing public here will not be too enthusiastic.
However, we have reached a place where the bulk of a film's profits are now to be found overseas in places like China. The latest Transformers sequel crashed and burned here, but China and overseas markets saved it enough to push the studio to green light yet ANOTHER sequel.
So while the American public is tired of preachy sci-fi Capitalism bash-fests, the rest of the world loves them.