Mr. Powell, this said with no disrespect and with a heavy heart...
This is a Wilderness area under the Wilderness Act of 1964. As such, no structures can be built. This is the most obvious reason nothing is built here. Anyone who has been involved in the solar powered latrine controversy will know this.
Secondly, even if you were to put boulders in place...it has to be done with human power. This means volunteers with hand tools. What you are talking about is beyond this. Again, because this area is covered by the Wilderness Act
Over the past winter, we had 4 people die in the Southern California mountains in the same places they always die in the winter. The Devil's Backbone and Ice House Canyon. Most, off the top of their heads, can't name these names like many can here with this spot. We have the same do something, do anything about this problem cries but in the end the best you can do is limit the problem. This means in this case telling those who do not want to be told to be through this area before dark. As someone who has told many not to go where it unsafe for them go in winter, the response is almost universal. I know what I am doing, as they walk into an avalanche zone.