[robertAngst]

But people will compare prices, and alert the media/friends when they find discrepancies.

I've seen the narrative change in the last few years, Fast food was deemed low cost, but a Calorie Per Dollar comparison showed that eating fast food is significant more expensive.

If a single company doesn't play by the rules, the world will be aware of the price difference.

[blihp]

This assumes competitive markets which allow them to do anything about it. For example (in the U.S. at least), when your local cable company raises prices for Internet services that effectively signals to the local telco that they can too. Sure, the market notices this but has few, if any, other options. (a big assumption is that you even have the option of both cable and telco ISP service in your area.) If all it takes to end up in this situation are NN's learning that implicit collusion is good for profitability, I'd argue that it really isn't a competitive market.

[robertAngst]

True, heavily regulated government sectors struggle from this(medical for instance), but online is nearly anarchy. I don't see Amazon having ability to screw customers (forever).

And those sectors you are talking about need serious reform that the incumbents DONT want.

[blihp]

Regulated sectors are indicators of markets that aren't competitive since regulation tends to come in after it's well past obvious that markets have failed. When Amazon gets to their end game (which they seem to be pretty close to IMO) I think you'll be surprised at how much and long they'll be able to screw customers... after all, most of their competitors will be long gone and the few that remain will be weak so who's going to be able to offer an alternative in the short to intermediate term?