Only partially correct. The other reason is because the gov't artificially keeps prices low for the consumer. The gov't pays farmers money not to produce excess food and/or buys their excess production. Then it turns around and artificially keeps grocery store prices low so the cosumer doesn't ***** about the price fo lettuce.
I grew up on a farm in Yuma, AZ. One of the major cotton and produce producing places in the US. The majority of the farms were owned by families. What screws the stats is they produce for one or two major corporations, Tanamura and Antle (Yes, we call it T & A) or Dole/Bruce Chruch. Thes mega-corps contract with family farmers to keep a certain amount of produce coming into their coolers. They tell the farmer how much of lettuce, melons, veggies, etc. they want and when they want it produced. They also approve the seed, herbicide, fertilizer, etc. used. In return the farmers get a guarenteed market and price for their goods.
So, while it looks like these are mega-corp farms, they really are the family-owned farms that everyone says is gone. They've just learned how to work with the corporations to their benefit.