Are you familiar with "The Wal-Mart Effect"? It describes the impact on local economies when a Wal-Mart opens. Spoiler: It isn't good. Far from being a net producer of good, decent-paying jobs, it tends to wreck the local competition, driving small-business owners out of business and into low-wage employment.

These days, "The Amazon Effect" is probably even more worrisome, because it's much more diffuse.

When companies can rely entirely on economies of scale, rather than innovation, to crush competition, it's possible to have immediate effects (such as lower prices) that are beneficial, but knock-on effects (such as the broader impact on the economy and the quality of jobs available) that are insidious and deleterious.