In the middle of 7 beraitot -- the last of which addresses increases to the cost of wheat, and then the Gemara turns to Megillat Ruth. Specifically, can you find wheat to purchase? If so, there's a dispute whether you can leave the land of Israel. Think of the family of Naomi, who left the land of Israel for Moab, because of a famine in that generation. Plus, all of the arrangements that needed to have been made for Ruth to end up with Boaz -- meaning, a good thing (that couple) that comes from bad things (the respective spouses' deaths, for example), which is theologically troubling. Also, another consideration of when one is allowed to leave the land of Israel - in terms of economics, again. Plus, Rabbi Yochanan's recollections, including of a time when the costs were down, but people still didn't have money for food.