Rfid tags are really cheap, some sellers advertise prices as low as 3c per tag but realistically 10c is probably the cost of a finished product (print, glue, maybe extra protection of the plastic)
That's the problem though - $0.05 is a LOT to a grocer, that's all they keep on a lot of products. Barcodes are free since they mostly go on labels that are being printed anyway. They could push for source tagging, but the vendor would pass on the cost, and grocery is a very price sensitive industry.
For apparel, on the other hand, source tagging is common - even before EPC on higher end goods, Calvin Klein used to sew magnetostriction tags into clothing. Apparel just has so much more price elasticity and loss prevention is a huge part of that industry. Tools are another industry where EPC and source tagging are common, once again, high dollar items with a lot of theft.
