You'd be amazed at the time it takes to get new construction contracts through the system. I had a project to put 10 miles of concrete barrier between east and westbound I-10 in Sealy Texas last year. They told me it was several years between when someone started to push for it and when we got the contract. We found major debris next to the new rails several times, and new smudges on the concrete almost daily.
TxDOT has a design for a rail that I think should go in a spot like that. It's about 5 feet tall, and made of reinforced concrete. No one should be able to go over the rail next to a drop like that.
How many of you drive through the mountains next to 500 ft. drops with no rails at all?