They already have roomba for lawns. If you can buy a 3D printed solar powered lawn roomba for the price of a sandwich once, and then have mowed lawns for a lifetime, why hire a person who will only do it once for the same cost?
I'm not trying to assert that sandwiches will definitely cost the same as a mowed lawn in 2114.
Your objection quoted above is just saying that a sandwich is worth a lot more than a mowed lawn in the robotic future. It's not clear to me why a self-contained hydroponics system with a built in 3D printer couldn't make sandwiches just as cheaply as the solar powered roomba could mow your lawn. OK it sounds a bit less plausible to us in 2014, but the actual equivalence was never my point anyway.
Robots do definitely generate more wealth, as do all increases in efficiency, but greater efficiency does NOT necessarily benefit everyone. In fact, that basically came to a full stop a couple decades ago, and technology advances is one of the largest reasons.
But I'm not claiming that the lower and middle classes will receive a standard of living increase proportional to their numbers. I'm just saying that all other things being equal, the worst that will happen is that their wages will stay the same. They won't be thrown into the poor house just because robots are creating a lot of goods very cheaply. If anything they will be better off.
Under a free market, increases in efficiency are likely to benefit everyone. But under capitalism, they only benefit investors, at the expense of labor.
Not sure what definitions you are using here.
In theory, having robots do almost everything, and having humans do just those few things that robots couldn't possibly do (not sure what those things are, but lets assume there are some), could mean that every human has a 1 hour work week and a 10 years working career, and they earn an inflation adjusted $1000 per hour for the work that they do. The economy would be able to support it.
This is an interesting claim. Aren't you assuming there's no more keeping up with the Joneses? If the economy ever resembled what you described, most people would spend their $1000 and then spend a lot of their free time doing labor to increase their standard of living in order to show off or attract a mate, or whatever. They'd either create something for themselves (like doing an addition to convert your house to a McMansion) or find some kind of freelance income to earn money for a nicer car, or nicer vacation, etc. It doesn't matter that robots could do things more efficiently because once they spend their $1000 for the week,
all they have left is their capacity to labor. So they would labor. They'd either try to sell their labor to other workers or else create things that they inherently value. Any way you look at it, you get:
1) lots of robots making cheap things, plus:
2) lots of humans laboring in order to increase their consumption.
Another way to look at it is that 2014 technology could probably provide everyone with an 1850's level of consumption with only an hour or two of work a week. But people would never just settle for that. They work more in order to consume more. It doesn't matter that their most basic needs are already met at very low costs.