As someone who's spent a fair amount of time hiking, it really depends on the maintenance of the trails. There's also often false trails even on maintained ones. Humans tend to be far more confident about their directionality than they are, and factor in weather or a dark mostly moonless night and its easy to hike in circles. Once lost and without easy landmarks, finding your way back is difficult as even if you locate the trail you're looking for, its uncertain if you're actually on it without glaringly obvious geographic markings to match to a paper map. We humans easily overestimate our ability to navigate.
I do agree though, not packing a GPS unit with a charging mechanism was a bad move. The one time when I really needed it was the one time I was hiking in white out conditions on a very remote mountain in Cascades and my buddy had an GPS (mind you in the early 2000s, thus archaic by today's standards), Setting a way point at the trailhead made my night a lot more pleasant rather than shuffling down a mountain in a blizzard, and hoping to end up near where we started. I wasn't unprepared and had a paper map and compass, and knew eventually we'd hit a forest service road but it could have made for a very long night in the cold as we marched back to our vehicle.
It's not dangerous if you have navigational skills. Most people, however, do not, or haven't developed theirs very effectively. I see it myself sometimes with other hikers at the front of a group—they take a wrong turn and suddenly have no idea where they are and start freaking out rather than just backtracking. Fortunately they're in a group, generally of people who can navigate and do know where they are, but when someone with poor navigational skills gets into that situation it usually leads to panic and bad decisions.
It's not at all extraordinary that a hiker of her age decided to go backpacking alone (which in this case she didn't—she was with someone else who left). It's a very common thing for people to solo hike and backpack. Carrying a small amount of gear is not a problem either—it's the norm. But navigational tools of some sort, even just a micro compass and a map, are generally considered an essential.
> It's not dangerous if you have navigational skills.
I'm ex-military so this point is probably why I don't understand the mindset, I just had navigation slammed into me time and time again. And we weren't allowed GPS so you got it right and you learning to recover if you did screw up.
> It's not at all extraordinary that a hiker of her age decided to go backpacking alone (which in this case she didn't—she was with someone else who left).
Another articles mention she started without them and stayed at a lodge with a number of other people so definitely took the decision to go alone. I guess the buddy/buddy thing is built into me too.
> Carrying a small amount of gear is not a problem either—it's the norm.
Another article mentioned she was carrying less than the normal 35lbs. Obviously I'm not sure what the norm is so defer to your experience.
I think she must have gotten lost and disoriented while very close to the trail and then spent a lot of time walking in the wrong direction without paying enough attention to be able to retrace her route even back to that first place where she realized she was lost. At some point she realized that moving was getting her more lost and she stopped. But at that point she was too far away from the trail for the searchers to find her.
In fact, I wonder if at the end, once she'd set up a permanent camp, if she stayed put because she was flat out afraid she'd get lost again if she left the camp even to go a few yards. This might have been a legitimate fear, but there is a way to handle it -- you leave "blaze" marks on the trees as you pass them so you can retrace your route. But maybe she wasn't familiar with this technique.
That does seem a possibility—or once she set up her camp she remembered the somewhat poor advice of staying put (this can be good if you're actively being searched for and likely to be found quickly, but once days or weeks have gone by can be bad to continue as your chances of being found decrease).
There are a lot of good ways to leave "telltales" you can follow once you're in a situation where you're lost. Branches forming an arrow on the ground back towards your camp, each within sight of the next, are an easy way to do it.
It seems extraordinary that someone can step off the trail like this and get so lost so near to where they need to be.
It also seems extraordinary that a hiker of her age, carrying as little kit as she was, decided to do this alone.