Urbanization made American farmers richer than before. Why? Because urbanization makes land in rural areas cheaper due to the population decrease. The farmer bought this land from their ex-neighbor. More extensive land motivates them to invest in better agricultural technology. Net result: they are getting more productive and richer in the process.  

What makes this research great? Because it counters our prejudice. We intuitively think that urbanization made both urban and rural are getting worse economically. This is not true.