Transgenics enable some solutions to what you're talking about, though. You can breed in disease resistance to your gourmet line of choice over a decade or two

Transgenics enable some solutions to what you're talking about, though. You can breed in disease resistance to your gourmet line of choice over a decade or two at considerable expense, or pop in an R gene for pennies, relatively speaking. There's absolutely nothing about transgene technology that implies monoculture; if anything, it dramatically lowers the barriers for breeding and developing new and interesting crops. Traditional breeding, driven by huge and colossally expensive GWAS studies, only benefits the biggest, most economically productive crops. The issue we have right now is that stigma prevents all but the most 'serious' transgenics to come to market. Fortunately, what we have so far are good transgenics, albeit ones that propagate monoculture. The future could look really good, quite disappointing, or even scary, depending on how we approach transgenics, both for regulation and as a culture.