The material and energy intensity of consumption, per capita, has increased exponentially over the past centuries. There is no reason to not expect it to continue to do so for the foreseeable future. Thus, you don't need an army of low-wage consumers to buy things from the wealthy.
You need people not being rich to have riches
Echoing another point made in this thread, but wealth differentials doesn't mean you need to have poor people. The least well off person in a society may not have everything they want - most people don't and probably should not, if we want aspiration and ambition to have a place in the future - but they'll have their basic human rights fulfilled (a roster that gains mass with economic development).
The material and energy intensity of consumption, per capita, has increased exponentially over the past centuries. There is no reason to not expect it to continue to do so for the foreseeable future. Thus, you don't need an army of low-wage consumers to buy things from the wealthy.
The "material and energy intensity of consumption, per capita, has increased exponentially over the past centuries" EXACTLY because of the creation first and constant availability of "an army of low-wage consumers".
People were taught to hold jobs in the way we do now, and they were taught to consume, in the way we do now. The vast masses of the people not only consumed much less, but made their own everything, from clothes and shoes, to vegetables and housing. Like an Amish community.
A decline in the middle class, e.g by migration of their jobs abroad, translate to a decline in economy, unless you can create new jobs at the same rate, which currently we can't, and the economy took a hit.
Echoing another point made in this thread, but wealth differentials doesn't mean you need to have poor people.
No, but a market economy needs people poor enough to have to work and at the same time rich enough to be able to spend money on things.
Automation can eliminate the need to have people working, but it cannot eliminate the need to have people spending --except if you move beyond a market economy.
You need people not being rich to have riches
Echoing another point made in this thread, but wealth differentials doesn't mean you need to have poor people. The least well off person in a society may not have everything they want - most people don't and probably should not, if we want aspiration and ambition to have a place in the future - but they'll have their basic human rights fulfilled (a roster that gains mass with economic development).