Netflix doesn’t stream from AWS. Rather, they’ve built their own video CDN[1] with PoPs all over the globe. All of their user-facing streaming happens from their CDN. Their AWS infrastructure is used for billing, transcoding, playlists, etc. Also, they perform some seeding of the CDN from within AWS, but the seed boxes themselves can seed each other as well.
All in all, they clearly do push huge amounts of data out of AWS, but that data account for a very small percentage of the total data that gets pushed out to clients via their CDN.