[amazon_not]

I get the economic theory, but I don't get how it would result in the actions prescribed in your example.

> Refusing to install another DSLAM means they can sell space on the existing ones at a higher price.

As customers as either on fixed term contracts or grandfathered in on existing plans, I don't quite get how ports on the DSLAM could be sold for a higher price.

I suppose prices could be raised as contracts run out and old plans are sunset, or when an existing user cancels and a new one seeks service. Is this what you mean?

> A monopoly must necessarily limit supply to increase profit. That means that turning away potential customers--even customers that spontaneously appear without advertising or recruitment--is an essential part of the business model

I get that the monopoly would limit supply by not installing new DSLAMs, but turning away customers? Why would a monopoly do that if there were free ports on the DSLAM?

Possibly raise prices yes, but refuse to sell no.