Major CDNs don't use Tier 1 providers to reach major eyeball networks in the United States. There are no ISPs who have sufficient capacity to the other networks

Major CDNs don't use Tier 1 providers to reach major eyeball networks in the United States. There are no ISPs who have sufficient capacity to the other networks. I'll cover why later. Netflix is what... 37% of Internet traffic? They aren't sending anything to Comcast other than Comcast traffic, guaranteed. Same with Verizon, AT&T, Cox, etc. Also, Comcast's backbone isn't large enough for someone like Netflix to inefficiently deliver data. Netflix is delivering the data locally, not using Comcast's national backbone. So sure... Comcast might offer "Tier 1" internet services, but they don't have enough connectivity to other ISPs to matter to major CDNs. Why? Because the other major eyeball networks in the US employ the same tactics as Comcast! They all want to force major CDNs to connect directly, for different reasons. Some ISPs do it to avoid paying "tier 1" internet providers, allowing CDNs to peer settlement free. Others do it to extort CDNs.