The prices are set by large farmers adding acres and acres available for sale are relatively scarce. When you consider the people doing the buying are at scale

The prices are set by large farmers adding acres and acres available for sale are relatively scarce. When you consider the people doing the buying are at scale (thousands of acres) and can spread the cost of very expensive equipment over many acres it starts to make sense. The marginal cost of farming another 80 acres in terms of time and equipment is quite low.