So yes, AWS, GCP, Azure bandwidth pricing is very high. Oracle is, amazingly, the outlier with lower bandwidth pricing.
Are there actual compute resources necessary to make endpoints and nat gateways work?
The reason for the hourly cost is a bit subtler than that, but we are working on the cost of this stuff.
(Source: Work at AWS.)
Regularly see EC2 interzone account for 1/3 of EC2 cost this would be a huge win if so (albeit totally ridiculous).