I don't know about GCP but Azure's egress costs go down as you use more and more dropping as low as .05/GB, and if you are using Cloudflare on top of it the costs go down even more. Then don't forget ingress fees, Azure charges nothing, while AWS charges ~.015/GB in. Since a lot of protocols rely on heavy ingress as well that starts to add up. AWS is notoriously expensive in bandwidth costs, that's nothing new.