I think they did make another Starship Troopers movie, but it was direct-to-video. Maybe they'll make a bigger part 3?
Starship Troopers 2: Hero of the Fedration was made by special effects person Phil Tippet. It was direct to video. Paul Verhoeven hinted at a third movie which will probably be released in theaters. Neither of the movies were true to the novel but they were good in their own right. I also like Paul Veroeven's satire elements that he adds in all his films (the same satire TV advertisments seen in the Robocop movies were done in the first Starship Troopers).