Makes sense to me if multiple people were to just pick up that name and use it. Just a bunch of copycat killers.
If it was all the same guy, then I have the same question I was JUST asking myself yesterday about Michael Myers (with that new movie coming out): how old would he even be now?
If Jason's first film was in 1980, then come on, he'd be at least, what, 60s now? Surely it can't be the same guy forever!
edit: Oh, I guess he had an actual birth date of June 13, 1946? Yeah, if they made a new movie now, no 75-year-old man is going to pull that off or look like that. lol He'd be going after people and having to stop frequently to catch his breath. Senior Michael is helped by already moving at an old guy's pace anyhow with just short busts of increased energy.