I'm 52. I liked them. But then, I'm a middle school teacher, and I read a ton of YA novels to keep up with my students. I like novels written for young people that resonate with everyone, that can move beyond the narrow social focus of the average adolescent.
The Hunger Games and sequels have all the right ingredients to attract young readers, modern readers: romantic drama for the girls, and plenty of action and violence for the guys (yes, these are generally required ingredients for adolescents, lol.)
For the rest of us, there are some very obvious connections to other things: "The Lottery," by Shirley Jackson, and television's "Survivor" immediately came to mind for me. My adult son says it's a derivative of Stephen King's "The Running Man." I don't know about that; I haven't read it or watched it.
The author herself, in an interview I read somewhere, linked it to the myth of the Minotaur.
For the blood-thirsty, impatient modern world, there is plenty of action, violence, and death. There is also, though, a deep internal conflict for the protagonist to wrestle with; one that asks us what we're willing to become to survive. The plot is founded on timeless social and political issues. I found the 2nd book, and especially the 3rd, to be full of irony. Finally, the ending is somewhat surprising, in that it's not a scripted, victorious, happy ending. Neither is it a total loss. It seemed authentic to me: some gains, some losses, much compromise.
If those things interest you, you might like the book. I know plenty of adults who do, although none of them are in their 70s. My mom is, but she wouldn't read it. Her ADHD prevents her from focusing on books these days. The action and violence would turn her away from the movie, overwhelming the other facets for her.
If you decide to investigate, I recommend the book over, or before, the movie.