I don't merely say this as a "fuck Amazon" reflex or a "fuck capitalism" reflex. I say it because it obviously would allow so much of the dying segment of mom and pop small business to become viable again. Just from a policy perspective it's a home run because it's a way to juice GDP, improve consumer purchasing power, AND reduce income inequality.
As a matter of fact I would suggest that Amazon as it exists is anti-capitalist. It is feudal. Capitalism is the deployment of capital and assumption of risk in pursuit of new value creating activity. Amazon is not marshalling new capital to innovate or improve its digital marketplace. Rather, Amazon simply owns digital real estate and extracts rent, like some kind of futuristic dystopian corpo-baron.
The best part of all this is that Amazon doesn't have to be forcibly nationalized or broken up or anything like that. The government just needs to support and endorse a good alternative, because Amazon seriously sucks.