Jeff, I think the definition of the term AI has "drifted" over time. I don't know offhand when it was first used, but I feel that originally it was defined as an artificial, human-level, intelligence. Of course, the problem becomes, defining "intelligence." Arguably, using the truck-bed caulking robot as an example, it is "intelligent" enough to be taught how to caulk a new truck-bed, similar to a person. Now, can it determine what the best way to caulk said truck-bed is from nothing, or previous experience? No, but arguably neither could a human doing the same thing.
Your line-worker would need to be shown by someone else, who was probably shown by yet another person, who was shown by the engineer who designed the bed, the best way to caulk it.
I would say the current level of AI is equivalent to an idiot-savant. Incredibly good, and focused, on one particular thing, but completely incapable of much of anything else (in the case again of your caulk-bot, someone steps inside the safety cage, it's not bright enough to realize this and proceeds to try to caulk the person, or clobbers them when it's swinging around, nor is it capable of realizing it needs maintenance of itself, it would keep working until it tore itself apart.)
Will we ever reach an AI of the sort Jeff is thinking of? Perhaps more to the point, will we *recognize* such an intelligence, or will be alien enough we won't know what we've got? To the first, I think eventually it's possible, but certainly not within my lifetime. To the second, I think that might be more likely, and perhaps, scarier.