I am a farmer and it is difficult as hell to create a non-GMO farm (non-GMO contaminated mulch and compost, non-GMO animal feeds, non-GMO source animals, non-GMO seed). The OP is correct in all points about Monsanto's power over seed production, but misses what SciAm (and almost everyone else) misses:
Genetic material is code being used in a production environment!
As such it needs to be protected. Code contamination (forks) need to be registered publicly and isolated with extreme prejudice from the production environment. We didn't write the code, and as far as I am concerned, I feel that Monsanto as a policy maker (by default or by lobbing) and any of the most advanced geneticists are script kiddies on a Galactic scale. We will get to adequate understanding it time, but that time is not now. Who gives a fk if you or your grandmother can live a longer or more pain-free life if the result is a global genetic seg-fault? I don't.
My answer is to set up my own isolated farm, as free of GM as I can make it. As I see it, existing organisms do have a genetic conversation (via viruses and other single cell organisms) and will resist and correct some amount of genetic contamination. Honestly I have my doubts that even this will work, but its the most I can do.
Food for thought.