[loewenskind]

If we ever get to the point that jobs aren't replaced that would mean that all work isn't needed so the typical rules of capitalism no longer apply.

Capitalism is just a mechanism for allocating resources, it's not any kind of moral judgment on anything.

[gaius]

It's more subtle than that; capitalism is to economics as thermodynamics is to physics. It doesn't matter what "system" you adopt, no economy can sustainably expend more wealth than it creates, just as there can be no perpetual motion machine. Capitalists are people who recognize this basic truth and act accordingly, equivalent to engineers who use the laws of physics to create machines. But what do we call people who claim to have invented perpetual motion...?