I would say most people in the rural areas migrates to urban areas because they believe or see that there are better opportunities there. Such as;

Educational aspect; people in the rural areas believe that education in the urban areas are better. Where as they have qualified teachers and they are more vast in learning, both in the theoretical aspects and practical aspects with better equipments.

Job aspect ; they believe the urban areas have better job opportunities with good salaries to keep them going and even acquire other skills that boosts their knowledge better.