MovieBob, claiming that elements of a movie are not quite as good as similar elements in movies made decades ago is not enough to justify saying a movie is unoriginal. Originality can be many things - not just the costuming or 'typecasted' evil guys, but also how the movie as a whole comes together and flows within its self-set constraints.
The Hunger Games combines many elements of previous films, perhaps, but it does it in a unique way that has every right to qualify as an original film. The dystopian future that serves as the setting may not be readily believable due to the flaws in the reasoning behind the show's popularity that you pointed out, but the setting certainly achieves the suspension of disbelief necessary in any great work of fiction.
The CGI of the 'evil death-hounds' could have been better, certainly, but their onscreen time is so brief it's hardly worth complaining about.
In short, every element of a film does not need to be entirely original if the resulting assemblage forms an original and compelling film in itself. We can play the 'blame game' until judgement day, but you'll never find a film which has not copied at least a fragment from another source.
The Hunger Games deserves its popularity.