Oh, sure, they can’t guardrail the whole thing. But this must be a bad spot, if two cars went over in the same place.
I remember driving along the French Riviera many years ago, and they only had selective guardrails. That was pretty scary, too, especially if you met a bus coming the other way. But great views.
Actually the dirt roads in our vicinity here in Vermont have similar problems, if not so dire. Deep drainage ditches where the car is certain to flip, and steep downhill verges. They can only afford to put guardrails on the worst bits, but that’s better than nothing.
Naturally, the worst curves offer the best views .. and I noticed in CA, where possible, they have those pull-overs for viewing at those points. Adding to the fun/excitement of a Western US mountain drive is that easily half of all vehicles are huge mobile homes.