I would think the cost of a 10 count box, labor, etc in pretty damned close to boxes for 20 thru 25. Add a nice chunk of cost to the final item.
I'm guessing it would make the 10 pack too pricey comparatively speaking, to a traditional box.
I wonder if the manufacturers think that Cardboard might be frowned on by consumers. Padron does it, and they seem to move fine.
I honestly wish they would do boxes of 30 or 31. I.e., a quasi months supply. Pete Johnson did it with his "P" series, and I thought it was great.