This has long been my argument for the long-term desirability of socialism.
But in my thinking, it's a bit more complicated than you make it out to be. Consumption doesn't really contribute to the economy in the relavent way; labor does. The only reason consumption matters now is that it returns the value of the labor's output to the capitalists. Then they can use the money to buy yachts and private planes and so on. Basically, consumption is a way of turning labor into general-purpose money. That's a fine model until you don't need the labor because you have all these fancy machines that can make everything (and design everything and clean everything and so on). So you lay everyone off. And then there's no reason you want the consumers because no one has given them any money to give back to you. You just make the private airplanes and swap them with the guy who makes yachts and call it day. And you're richer than ever before because you're massively more productive.
Now a few different things can happen: one is that everyone else just starts new businesses that employ the labor so that they can benefit from it, as sort of a second-tier economy, which exists until its elite accrue enough capital to build their own automation and the cycle repeats. That doesn't seem too likely. What seems much more likely is that everyone gets really mad that the current system doesn't provide for them anymore and demand a cut of all these robots' output. Maybe that happens voluntarily on the part of the capitalists (I think this is more likely, on reflection, than it sounds) or maybe it involves some government-sponsored coercion or a populist revolution. I don't really know.
But in my thinking, it's a bit more complicated than you make it out to be. Consumption doesn't really contribute to the economy in the relavent way; labor does. The only reason consumption matters now is that it returns the value of the labor's output to the capitalists. Then they can use the money to buy yachts and private planes and so on. Basically, consumption is a way of turning labor into general-purpose money. That's a fine model until you don't need the labor because you have all these fancy machines that can make everything (and design everything and clean everything and so on). So you lay everyone off. And then there's no reason you want the consumers because no one has given them any money to give back to you. You just make the private airplanes and swap them with the guy who makes yachts and call it day. And you're richer than ever before because you're massively more productive.
Now a few different things can happen: one is that everyone else just starts new businesses that employ the labor so that they can benefit from it, as sort of a second-tier economy, which exists until its elite accrue enough capital to build their own automation and the cycle repeats. That doesn't seem too likely. What seems much more likely is that everyone gets really mad that the current system doesn't provide for them anymore and demand a cut of all these robots' output. Maybe that happens voluntarily on the part of the capitalists (I think this is more likely, on reflection, than it sounds) or maybe it involves some government-sponsored coercion or a populist revolution. I don't really know.