Comment by PeterisP

The original article seems to assert that there are essentially no non-grinder buyers (which would be a key distinction from the gold farming) that in this case the existing grinders are selling the items to the new-potential grinders who are paying an initial investment with the hope of recovering it by grinding - if that's the case, then it is essentially a classic pyramid scheme where you as a newcomer pay so that future newcomers would pay you more afterwards; which works until the stream of new incoming money dries up.