It's not only about cost. Networking is complex and especially for streaming companies. 1.) They need to know which pipes (to which carriers) are used at what

It's not only about cost. Networking is complex and especially for streaming companies. 1.) They need to know which pipes (to which carriers) are used at what percentage 2.) Be able to upgrade those pipes as they please 3.) Be able to cache content locally with those carriers/ISPs All of those 3 points are not really possible with AWS.