>I'm not sure whether "relentless commodification" is such an explanation
>or only a further description of the facts to be explained
You're right that it's more description than explanation, but I think the explanation is this: that process of commodification is driven by capitalists who want to make a buck. So they see existing areas that are already commodified as ripe for a new kind of commodification (e.g., Martha Stewart cuts a deal with KMart to turn ordinary towels into branded towels) or nonmarketized areas that are ripe for fresh commodification (e.g., laundering, food service, child care, commercial education, etc.). Since commodification requires workers, there's long been new demand for new workers.
Doug