Ummm...

Quick back of the envelope [1] shows that the EC2 pricing is still only about 60% of the Aurora price, and something less than half of the RDS/PostgreSQL price, even counting the intra-region transfer.

There may be some transfer patterns and database sizes that cause the Aurora implementation to end up less expensive, but I think under most use cases Aurora is _more_ expensive, and RDS _much more_ expensive.

Just because the intra-region transfer isn't itemized doesn't mean that you aren't paying for it. Heck, the fact that the mark-up is so _low_ is pretty impressive, to be honest.

[1] Assumptions: [db.]r6g.large, x3 for ec2 instances, 1 year reserved capacity with monthly payments, 100GB storage, 1TB of intra-region transfer/month.