Just to chime in..
First to the family, friends of the three and to the SAR folks, my heart goes out to you all. From what I have read about the three, they are first rate climbers who got caught with some bad luck. It looks like they did their homework, and made sure people were aware of their itinerary
To the non-climbers, a couple of comments that might help you understand some things..
The first, is that while the three were/are hoping for help, they were more then likely prepared for self-rescue. When technical climbing such as on a big mountain (such as Hood), one cannot simply sit down and say "well I will wait here for help". This is not a hike in a park along an established trail with a ranger passing by. The most important safety practice that any mountaineer needs to take to the mountain is self support.
Some speculation on the reason for the two caves. It could have been that the two came back, and tried to assist the third (Kelly?) back to the summit, found that he couldn't make it and re-dug a 2nd cave, and then proceeded for help again. The discarded gear could have been Kelly's, which might not have been needed and therefore just extra weight.
On the "Y", it looks like an anchor setup, nothing more. In the terrain that they were in, it is possible that they anchored themselves in the cave.
On the terrain that they are dealing with. Here are some steepnesses of ski runs, 30 degrees is maybe a blue run, 35 degrees a black diamond, and 38 a double black diamond run. From a earlier comment, the route that was being climbing was around 60 to 68 degrees. (BTW, this angle is usually too steep for an avalanche since the snow just sloughs off, -- so the largest avalanche danger is from the terrain above where it may not be as steep - most avalanches start on slopes between 35-45 degrees). The other thing is that the type of snow climate in the PWN, the highest danger of an avalanche is during and right after a storm.
The problem with requiring mountaineers to carry radios, locating beacons, etc., is that it simply is a false sense of security, and would probably lead to more rescues of people who should not have been there in the first place (see above comment about self-support). The exception is avalanche beacons, and the main reason for that is that they are designed for a team self-rescue. In an avalanche, one has minutes to find someone who is buried. Anything over 30 minutes is usually body recovery.
As also stated earlier, one of the big concerns among climbers is regulation, especially after a huge media event such as this. Part of what makes climbing - climbing, is that it's an endeavor that allows one to test themselves in an environment where there is no regulations. A (getting geeky here) Star Trek Next Generation quote sums it up nicely
"If you can't take a little bloody nose, maybe you ought to go back home and crawl under your bed. It's not safe out here. It's wondrous, with treasures to satiate desires both subtle and gross. But it's not for the timid."
To those concerned about the cost of the rescue, here is a study showing how climbing stacks up to other rescues http://www.americanalpineclub.org/pdfs/MRreal.pdf Bottom line, climbers are not the "problem". However they do end up being a target because of the spectacular media events that sometimes surround the rescue. The reason why the media is attracted to events such as this is because it's "news", they don't understand it - it's not mainstream, why would anyone go do something like that, etc.
Again to the family and friends of the three climbers, my thoughts and prayers go out to you.