>Historically, it's been impossible to differentiate "productive" and "un-productive" labor over prolonged periods.

Not true, either you helped in the production of sufficient food to allow a surplus, and thus enabled specialization of labor, or you didn't.

It is only the addition of billions of "virtual laborers" fuel by underpriced energy in the form of stored ancient sunlight that the labor market became so distorted. The past 200 years have been the anomaly, not the norm. The pulse of underpriced energy is coming to an end.