It may not "need" to be[0], but the externalisation of poverty is precisely how the particular quality of life that the lower classes in most developed countries enjoy is maintained - from the workers that make their fast fashion to the ones that assemble (or mine raw materials for) electronics that they cannot afford themselves.

0. At some point in the not-so-far-off future we will get around to automating all of these things, but until then people have become too deeply entitled to commodities produced by other people that are paid poverty wages.