As someone with experience with hydroponic systems and field crop systems, I see indoor agriculture as co-existing with traditional farming. There are lots of factors to consider: market timing versus production costs being a major factor. Manipulating the growing environment indoors can have many advantages- just tour Disney World's "The Land" exhibition and you'll see amazing yields. Technology is also making traditional farming more efficient as well. The important thing is that even as population grows, the food supply is maintaining its capacity to feed us all. Now if we could just do something about getting all this extra food to the people around the world that need it . . .