WB, I admit, you do seem to run into a lot more dumb hikers than I do, but then again I hike mostly in Northern California. We don't have much graffiti or broken window glass at our trailheads either. I lived in Wrightwood near Baldy for a year and San Diego for 15 years, so I think I can speak fairly to the differences in hiker intelligence between SoCal to NorCal, as a general observation of course.
Getting the word out about this location serves as an information campaign - making people aware of past accidents there, and also a chance for people to grab a hand-size rock or two on the way up from Trailside Meadow or on the way down. Minor trail work, well within the Wilderness Act. This situation happens all over the wilderness where a trail is on solid granite and easy to lose. The common solution is to erect cairns (ducks) or line the trail with small rocks. Or perhaps build a small guidewall.
Looking at the Google Earth shots, it appears that a small line of rocks on each side of the trail would do well to guide hikers through this section over solid granite. I even see a small borrow area just below the second switchback where hikers could pick up a small rock or two.
Lastly, again, any plan would be cleared with Inyo. We're just talking hypothetically at this point. If we can't get over the "no can do" stuff, than nothing happens, as usual.