That argument is false today, and will be false for decades. I am convinced, however, that the era of widespread sustainable agriculture will be far in our future, after humans have stopped their growth in numbers and material wants, and after the concomitant replacement of the market-drive out of our economic system. In the absence of growth, sustainability is possible. At postgrowth time, extinctions will be massive, topsoil will be minimized and toxic, air will be foul, fresh water will be contaminated and in short supply, and many scarce raw materials will be replaced only by the highest level of technology. Our crops will not find environments anything like those to which they were domesticated.
Designer crops that produce both food and other valuable, engineered products make a lot of sense.
Genetic research can and will do better. This research requires altering genes in vitro and putting them into plants to see how the plant is changed. The people of the world should be pleased that much of this important genetic research is carried out, openly, in public teaching and research institutions such as the University of California. In my opinion, it does no good to point the finger of blame when the course we will travel is largely cast. It should be an exciting, transcendent ride.