except, they don't, actually.
exchanges are designed for traffic EXCHANGE. I.e., useful traffic for you, useful traffic for me, and we split the interface and cross connect fees. we both pay to be in the exchange space.
when you don't have an exchange relationship, one side is now the provider, the other is the customer. which is the relationship the end carriers are demanding they should have with netflix (just like they have with all the other large content providers who want access).
Netflix is bitching because their main ISPs exchange numbers go wonky once a certain amount of the traffic they present to their peers is netflix only. it skewers the exchange numbers against the 3rd party provider, and creates legal issues in their peering relationship.
since exchange connections are meant for exchange, there is zero motivation to upgrade because a single end site is performing poorly across that link. how do we know it's the link? VPN out another link and run netflix from a carrier that has a better connection back to Netflix and it runs fine. bypass the congested link and there isn't a problem.
why does it work this way? simple. once a single entity begins to impact a publicly shared connection due to it's volume, the traditional (and btw, technically sound) way to ensure that shared connection continues to perform well is to optimize the route for that single source, by putting it on it's own interface. since this is now a dedicated connection, standard transit rates apply.
Netflix is objecting to paying the standard transit rates by calling out those carriers and pretending they are being asked to 'double dip' (which is something only someone with zero understanding of how things actually run on the network would say), Netflix et.al. is over simplifying a technical issue in order to use the standard class envy/hate to their advantage...
people fall for it because they want to believe there is some all powerful evil corporate monopoly conspiring to put netflix out of business so they can 'force' you to buy their own streaming media service...
but that really doesn't make much sense. they can't give that stuff away now. if you have cable service, they are already giving you as much 'free' media as you want via their standard broadcast packages.
since the media streaming business, (technical challenges of network infrastructure aside) revolves around obtaining and maintaining licenses from the original content creators, the battle isn't in the access side, it's in the legal side. so long as netflix can maintain a library of content people want, esp when they lock it up for media streaming, they are effectively blocking everyone else from competing with them!
but I'm sure that's 'ok'....