They don't have a significant advantage. The price of non GMO food is only slightly higher. Most of the cost of food is from processing and transportation, not at the agricultural level.
But to the farmer, GMO yields are significantly higher, and can be the difference between making a profit or a loss. It also means less use of pesticides, and safer pesticides, among other possible advantages like disease resistance. On a world scale, we produce more food with less land, which is definitely good. And especially important for the third world.
The future of GMOs also has a lot of potential. We could engineer plants with many times greater photosynthesis, or the ability to grow in salted land, to not be damaged by frost, etc.
If all the factors you mentioned don't lead to a big price difference, then that's the market telling us that they don't really matter. If production is cheap, then there's a lot of supply, and there's little to be gained by optimizing supply.
I stand by what I said. You cannot simultaneously have GMOs that are a significant improvement overall without them negating the "minority" argument, and ones small enough to be undermined by a vocal minority shouldn't matter.
"many times greater photosynthesis, or the ability to grow in salted land, to not be damaged by frost"
If any of those were a real problem, then production would be a greater percent of the final cost. If changing those doesn't really change the final product price, then they're not important.
Just because something is only a small portion of the final product, doesn't mean it's negligible overall. If say it raises the price of food by 10%, that's 200 billion dollars lost in just the US. Probably the price increase is smaller than that, but it would still be a non trivial amount of lost value.
And again, the real issue is with third world countries, where the price of food can mean life or death. These countries depend on the first world to innovate in things like GMOs. If we stop doing that, because people won't buy them, we hurt the world's poor disproportionately.
But to the farmer, GMO yields are significantly higher, and can be the difference between making a profit or a loss. It also means less use of pesticides, and safer pesticides, among other possible advantages like disease resistance. On a world scale, we produce more food with less land, which is definitely good. And especially important for the third world.
The future of GMOs also has a lot of potential. We could engineer plants with many times greater photosynthesis, or the ability to grow in salted land, to not be damaged by frost, etc.