(Income Gap: In fulfilling those hopes, however, Korea faces some potentially disruptive problems. Some are social. For all the progress, deep pockets of poverty exist throughout the country. In Seoul, glistening high-rise apartment houses jostle with warrens of slum housing; in remote rural communities people are still eking out subsistence livings. As a result, conspicuous consumption by a nouveau riche elite has become a real source of friction. In contrast to Japan, which has managed to spread its postwar wealth relatively evenly, Korea is beset by a widening income gap between rich and poor.)What does “deep pockets” mean here?