They can communicate with their families and talk to the outside world. They know efforts are underway to rescue them. I think those make a huge difference in keeping them hopeful, compared to someone trapped that has no idea if anyone is even looking for them.

I read that they haven't told them how long it will be until the rescue shaft will be ready. I'm not sure whether it's better to think that you will be rescued "any day now" or that you are going to have to tough it out for three months with 33 sweaty men.