It's different this time. Artificial intelligence will allow robots to do anything a human can do better than a human can do it, so when new productivity outlets arise it will be robots that fill the need, not people. Our tools are on the brink of outgrowing us.
It's always different, no matter when.
But the new "productivity outlets" as you call them, can and should be in environments where humans cannot work, from the raw vacuum of space to hotspots like Fukushima and Chernobyl. There are jobs to be done that humans don't want to do, or cannot. The potential for mapping underwater sites, underground sites is extreme for small robots as well.
Replace humans? Nah.
As for AI, who is going to program it? What will it define as "efficient"?
Consider that beyond utility, not one thing on the planet, living or inert, means jack to a computer.
Trees? Plants? Animals? Computers do not have a food chain. None of that matters except for materials, and those things may be in the way of extracting them--oh, and humans, too. Some parameters of a planetary environment simply aren't necessary, and may even be detrimental. Free Oxygen only heightens opportunities for corrosion, for example. What we humans consider necessary might not factor in at all.
The concept has been explored almost
ad nauseum by the science fiction community.
From a human standpoint, these machines are tools, tools which can be used to improve the 'human condition'--or eliminate it.
The real use I see for AI is to mine and utilize resources off planet, and even in parts of this planet we cannot access as humans.
Imagine, AIs mining the asteroid belt, refining ores in space, constructing entire bases and ships in that cold vacuum, without placing massive numbers of humans in peril during those operations.
But here's the catch. If you give those robots feelings, are they going to want to surrender such constructs to humans? Will they be subservient? Will they want to keep what they make? How long will it be before a semisentient machine decides it is better off running things by machines, for machines, to the exclusion of all else? (Just look at the numbers, pathetic, frail, weak, human, as they phase you out.)
Without feelings, you run into the concept that they have no loyalty to the meatbags who created them and are only in the way, a tremendous 'waste' of resources for things that can't even work in vacuum. Throw a couple of rocks and they gt those pesky humans off their mechanical backs.
We have already observed in human history that when people start acting like automatons, following a strict but flawed set of parameters (and they are always flawed, usually because of a narrow focus in their goals), that the result is death, destruction, and misery, either out of complete disregard of the effects of the process, or in some notable instances, as a result of the process. Historical attempts have been made to conduct those matters more efficiently, through the wonders of assembly line techniques, efficiency studies, and even mechanization, and the result was some of the most efficient death, destruction, and misery on the planet outside of extreme natural disasters, but hardly something we would deem 'beneficial', unless, of course we sought to eliminate entire populations. Humans being human, that also failed, with few exceptions.
