We will have to agree to disagree. I don't doubt that food science as a whole will develop, and that there will be an increased demand for scientists in that field. But I don't think all of specializations, including the niche ones, will observe an equal rise (if a rise at all), because it is very difficult to predict what direction the technology will take us.
Take for example your argument: "The other process would be to breed better varieties, which requires a long cycle of plant breeding. Whether it's classical breeding or genomics assisted, it's a long process. Want new crops a decade from now that have the ability to be grown in a saline soil so that the world can start to use acreage that right now is going to waste? Great -- better get started right now. "
For me it actually underlines two major reasons why I don't think plant technology will remain our long-term source of edible biomass: long life cycles of plants and dependence on land.