Rural land values will remain low until there is significant economic activity and particular demand for land IN THAT PLACE. To the extent that land, say, 10 or 20 miles away is just as suited for the user's purposes, the next piece of land that comes on the market is quite adequate, and the rural business can locate wherever, not pay a premium.
I am reminded of a famous passage from Henry George's book "Progress and Poverty" (whose subtitle is "An inquiry into the cause of industrial depressions and of increase of want with increase of wealth ... The Remedy") known as The Savannah. http://progressandpoverty.org/files/george.henry/pp042.html, starting at the 10th paragraph (the paragraphs are numbered in this particular file).
Incidentally, George dedicated P&P as follows:
"To those who, seeing the vice and misery that spring from the unequal distribution of wealth and privilege, feel the possibility of a higher social state and would strive for its attainment."