In Gen. 36:6-7, for the second time in Genesis, we learn that two rich men could not live in the same land. Esau and Jacob had both grown very rich over the years, and owned many possessions, including much cattle. Unfortunately, the land could not support so many men and so much cattle, so Esau was forced to leave. Unlike today, when the rich tend to cluster in small communities and keep the plebeians at arms' length, this was not possible when a man's riches were only as good as the land that supported them.
For the curious, the first instance was when Abraham and Lot separated ways in Gen. 13,