Pretty sure most of these missing people got lost and died of exposure or attacked/eaten by some animal.
I'm still staying out of deep trails in national parks: A park ranger I dated for a bit told me about a burial ground in one of them and how the horses would get spooked by supposed ghosts and other paranormal things she'd experience i.e. footstep sounds and voices around the property at night. Could be anything honestly, she might have been making it up.
OT She was super nice at the time but I stopped dating her because she literally dressed like Peggy Bundy. She then stalked me and called me on my wedding day.