Using social media to crowd source the manual labor seems like a good approach, but if a volunteer group takes it on, that's even better. Despite all the "dumb hiker" stories on this thread, I think there are plenty of hikers capable and willing to pitch in, if they were just aware of it.
This thread has turned into a big "no can do" "hikers are stupid" bummer. I hope the families and friends of anyone who perished at that spot never reads it.
"No can do." Actually, all I have said is do it right. Not no can do. Based on your words, I would say I am a lot more involved in hiker safety than you. I have doing passively for years, actively for the last four years. The only thing that has a chance of working is education. The Wilderness Act of 1964 comes into play here as does the fact this is a sparsely populated area. You cannot get critical mass for a volunteer group. Nothing is going to happen here without an organized volunteer group and under the auspices of the Forest Service.
I don't write for the families. I write for those who pass this way in the future. What is past is past. Learn from it, talk about. Keep it pertinent. So the next group of hikers who go up there know about Powell and Likely. Do you know about Lopez? Nguyen? Goodman? I use these names all the time because I don't want people to end up in the hospital or cemetery.
"Hikers are stupid"...actually to a great extent the meetup/modern hiker are but that is at best a tangential issue.
People willing to pitch in, that is something that I have not found in evidence. They willing to put a few rocks up...maybe. They are not willing to do the heavy lifting. Getting qualified by FS to use a pry bar and other tools required do something permanent within parameters of Wilderness Act that is doing something. Phone calls to a RSO shows very little.