Tony Murfin of GPS World provides good insight into the current state of GNSS in production agriculture in his GPS World article about feeding the world's growing population. Demand for food worldwide is expected to double over the next 50 years - and ag producers worldwide must rise to the challenge of growing that food. Much of that increase must be realized through greater production efficiency from the same land.
While the rate of adoption and implementation of GNSS technology varies widely, ag producers can realize appreciable gains by employing these tools to increase production output while managing input costs of seed and chemicals. Further efficiencies can be realized as technology becomes more widely adopted, and field-specific data is shared between producers, seed and chemical dealers, and agronomists. The success of GNSS in this role fundamentally revolves around the collection, sharing, and efficient use of data as a tool to promote efficient production in the field.
Hopefully this ag automation will facilitate the productivity needed for keeping pace with worldwide food demand. But the bottom line is: if you enjoy eating, say "Thank You!" to a farmer.