Oh lord, are you serious? You think the fact that James Bond has a bunch of movies with some similar characters has murdered the franchise, whereas a 5 part series like Saw (which should have never really made it last a half of a film) is still fresh?
To begin, I didn't use the word "fresh", and I wouldn't because it's too ambiguous. I also didn't say "murdered the franchise", again that's ambiguous and a loaded term. What I did say is that Saw hasn't lost any quality in the first 4 movies. I'll stand by that, although I probably wouldn't have the first time I saw them. I also said that they're trying to squeeze James Bond for all it's worth; since they're still making James Bond movies after nearly 50 years, and the only real relation between them is the names of the characters, I stand by that as well.
You obviously aren't a big fan of Saw, which is fine. But if you watch Saw II carefully, you'll see characters that ended up in Saw IV and Saw V present, and they aren't there by coincidence. Also, there are plot elements that you might overlook in earlier Saw movies that are explained in later ones. I could name a bunch of them, and a bunch of still unexplained stuff, but I won't. The point is, the Saw movies were designed to be a series, in a continuous world, and will end at a certain predefined time. Once everything is wrapped up, if they go back and add more sequels, I'll probably say the same thing.
I feel the same way about the Hannibal Lector movies -- if they want to keep making them, as long as they still fit into the overarching story, I'll be happy; but if they start adding sequels for the sake of adding sequels, I'll be upset.
I guess the main difference, to me, is that I don't mind having stories that span over multiple movies, if that's how it was written/designed. But I do dislike having sequels for the sake of having sequels.