Now you got me started! FYI, I get my produce from a collective of small farmers. Some reasons why American large-agriculture is so wasteful. (1) We never pay the full cost of water or energy over their lifetime. We only pay the cost of extraction. (2) Agricultural use gets a discount on those things, instead of getting surcharged. (3) Big farmers get all kinds of government incentives and bailouts, regardless of party, because everyone wants to win the "Iowa vote". (4) Especially under Obama, huge tracts of lands were devoted to grow corn, not to feed humans, but to generate ethanol for "clean energy". The price of corn went from a dollar for a dozen ears to a dollar an ear. (5) Then there is the whole meat and industry, and its demand for feed and land. At age 3, in a heavily meat-eating society and as a form of protest, I made the personal choice to be a vegetarian, which has become a lifelong way of life. Now if I advocate that as policy in today's America, I'll be immediately deemed a leftist radical.

As you say, it all goes back to the settler mentality - the Homestead act and the slaughter of the buffalo.