From Adam Smith on, we expect rivals to get together to conspire against consumers. But this shopping season, we have Amazon and Walmart engaging in cutthroat price competition.
The effect should be good for consumers in the short run, but bad for retailers generally. As the price war expands, however, it is almost prohibitively difficult to think of all of the general equilibrium effects of this, so it is a shame that we won’t be offering Industrial Organization until next year. Look for this example ad naseum in ECON 300 next term.