It's very much by design. They want ingress not egress to create "gravity." The end game is for virtually all compute to happen in the cloud and be accessed only by thin client. This pricing drives things in this direction by making companies that would use the cloud to just service local compute less profitable than companies that host everything in the cloud and provide only web or other thin client access.

There are providers that don't do this, but they are much less batteries-included. The best bandwidth deals are via bare metal hosting which is basically just box-in-a-rack rental. You can get bandwidth there by capacity rather than transfer quota. It's many many orders of magnitude cheaper.