I mean they clearly can't dodge bullets, they've been shot in every movie.
But the thing you're completely leaving out is they have personalities. And those personalities are arrogant, egotistical.
Every Predator we see die in a movie pretty much does so because of its own hubris.
Jungle Hunter got distracted with the taste of victory. City Hunter savoured a kill he hadn't earned yet. This was then repeated with Chopper and Celtic, and Scar kind of blended the two - he was so busy savouring an actual kill he let his guard down.
The guy with the tusks in Predators got caught by a trap; Falconer got himself into a duel where size and strength didn't really matter and lost. Mr Black got distracted.
Feral is the best example of this. He's so sure he's invincible because nothing has really hurt him all movie and so he falls into a trap because he has had no reason to take these human things seriously.
So they're bigger and tougher and older, sure, but they're also cocky bastards and that gets them every. Single. Time.