They do work perfectly in some fabrics. I've replaced metal grommets with hand stitched eyelets in cotton tents and not had them fail thereafter. The reason they don't use them commercially is time: you need to pay about 25 per hour for handwork like this, and you can really only do about 4 an hour... Compared with banging in grommets by machine... Well, you can see the difference! Some sailmakers making canvas sails for things like period accurate tall ships and Thames barges DO make the eyelets by hand. So do some of the re-enactment tent makers. After all, if they worked well for hundreds of years, they will still work well today. But it is a level of insanity that not all aspire to! <img src="/forums/images/graemlins/crazy.gif" alt="" />

Handworking eyelts in modern artificial fibres is a complete pain in the posterior, and that is one area where I'd go for the plastic ones set in 2-3 layers of the fabric, probably glued together with seam sealant for added strength. Either that or the stitched in tape loops... Depends on the abrasion characteristics, really...
Mad sewing witch!