1. oodles of hostels
2. trail magic
3. friends and family meeting up with hikers
4. slackpacking
5. cell phones

I wonder how low the success rate would be for thru-hikes if not for the increasingly more common instances of trail help?

I'm not talking about light-weight gear which helps the physical side of hiking which obviously carries over to the mental side. I'm referring to the opportunities for spirit raising things like a soft bed, a call to a loved one from a mountain top, a meal at a road crossing, etc.