Fortunately: there are still a lot of people who bring home-made food to work on most days, lots of produce bought at local markets. Farmers are not stupid (not even "simple people). Many of them are college educated guys who can find out about the damage these crops cause (if not health, environment - google "green deserts"). They are (at least at the organic fair) a new breed of farmers who sell you books and would give you their business cards that show they are agricultural engineers.
Unfortunately the markets are not all organic and not all farmers understand or care. Large companies do not care. It also became a trend to go out to eat for every lunch and Mc, BK, KFC are packed at lunch hour on weekends while many typical restaurants are empty (some are greasy, heavy, sugary, but still "real food"... and supporting local...
Also just like the school of medicine denying natural cures and promote "cut or medicate" practices, most schools treat organic growing as woodoo that only cuts it on a small scale (if at all). There is a group of hip looking quiet group of young people selling a bunch of different organic veggies. Turns out they started growing organic on university property and now they got a lot of space. If their experiment succeeds, the university is going to add organic growing to the curriculum. I don't know too much details, but as far as I understand they income helps the school and I think they keep some of the profit (or reduces tuition) - not sure about this.
I think farmers really understand, that as far as they sell healthy stuff to their clients they will come back longer. Corporations do not care because the share holders are the same guys who make $$ on the shitty food, booze, cigarettes, then healthcare and prison for profit when things go south. Farmers also know, that if they sell directly (and in Costa Rica they do not have to give an invoice like in e.g. Hungary) to clients they make a nice profit and they sell nice, fresh stuff. As soon as it is on store shelves or import, it is early harvest, then possibly some "harmless" chemical wash that keeps the stuff fresh for days on the shelves.... plus larger quantities are required, profits go, then you have to produce large quantities. Fertilisation, land overuse ... etc. etc :)
Anyway, if people tried to buy local, eat fresh and at least reduce animal based, we could feed the planet just fine. Hell, vertical hydroponic gardens are not science fiction, if land is an issue, you can go many stories up.