I haven't read the book but the argument that food writer Barry Estabrook makes in Tomatoland, as I understand it, is that the tomato is completely unsuited for growing in the common tomato-growing areas of Florida. The humidity and frequent rain results in disease. Since the tomato ancestors are found in some very dry country in South America, the domestic plants should be healthier in a similar climate.
I don't know how true this is but I was just trying to get some idea about the climate of Peru after I read about a trip that some UCDavis horticulturalists (& tomato specialists) took to Canta, Peru a few years ago. Climate data isn't easy to find for Canta but, Wow, this is a very dry country!
It depends on how high in the Andes those tomato ancestors are but it seems the researchers were quite close to Lima. That city is incredibly dry even with humidity and fog coming in from the Pacific Ocean. Up around Lake Titicaca, there is about 24 inches of annual precip. Rain falls mostly during the warmest months of the year. Still that natural source of water is only coming down at about 1" each week.
I live where 1" each month during the growing season is about the best one could hope for. I irrigate the tomatoes along with everything else in the garden. Still, I know one gardener who follows the same practice that her father had - cover the ground with heavy mulch after the snow melts in late winter, set the plants out in the spring and never apply additional water.
If they have a chance to grow accustom to it, and send down a substantial root system, it looks to me that tomatoes certainly do not need more than 1" each week and would probably be fine with less than that.