The word "efficiency" looks to be a bit misused here based on what people normally consider when seeing the word, but I can see where the author is coming from. Pumping the ground with herbicides, pesticides and fossil fueled based fertilizers are very efficient methods to produce a lot of food in a short time in small amount of space, but from a system/planet perspective it might not be that very efficient at maintaining the environment long term.

That said, industrial farms that do not use destructive methods for farming are going to be much more effective than what an individual can do in terms of growing their own food. As such, are more optimal strategy in terms of personal efficiency would be to focus on their own strengths like app development, doctoring and so on, and then use the revenue from that to buy exclusively from farms that are long term efficient for the planet. I would claim that growing your own food is a bit of a middle ground.