The cloud vs. on-prem argument often seems to ignore the (enormous) middle-ground. Just because one portion of your architecture would do well to be run outside the cloud, doesn't mean you take out all the other parts you don't want to deal with yourself. Furthmore, "on-prem" might mean in your building, in someone else's building co-located and you rent space and control it, or in someone else's building where they deal with most hardware, etc.
That said, maybe Canva has considered a non-AWS solution and decided against it. Or maybe they've gotten certain better deals from AWS. We can't really know for sure on the outside.
- Consistency. Instead of saying "Oh look in AWS for this app, Azure for this one, and hetzner for this app, except it's test env is in AWS", it all just lives in AWS. It massively simplifies docs, onboarding, and reduces the amount of one-person specialised knowledge.
- Engineering Costs. Similar to above, but in terms of engineering, there's less to know and understand. Instead of needing to know how the AWS load balancer routes/connects to a VM somewhere else, and how that VM gets it's blob-storage-data from azure, we only need to understand AWS concepts.
- Vendor Lock In. Yeah, it's there. If we have a service that uses data from S3, there's egress costs from S3 to <other provider>, but not with EC2. We've consciously accepted this lock in for the time being.
Now, we're a 50 person company so YMMV, but the above tradeoffs plus an "opinionated" setup in AWS (everything on ECS, logging to Cloudwatch, RDS for DB) drastically reduced the "ops" overhead on our side after the initial setup. If I started over, I'd make the same decisions again.
Okay? I never said that sticking to a single cloud provider isn't appropriate for some (or maybe even most) people. It's good that you have a setup that you believe works well for you.
Very few people should really be using S3 at any serious scale is my thoughts. The cost savings are enormous (plus cloudflare for example replicates your data a lot closer to users for no extra cost, significantly improving performance). The cost savings can be absolutely enormous for very little/no additional complexity given how many providers are compatible with S3, and the fairly 'boring' nature of S3 compared to other technologies.
Because I've done small scale and can tell you I'd run S3 in the future.
This is where I think the FCC should take action.
To the extent that this issue is a mutually agreeable arrangement between you and Amazon, it seems obnoxious but does not seem like it rises to the level where regulators should take action. But it affects third parties too: specifically, it prevents non-AWS-hosted vendors from effectively marketing their services to you. In that regard, I think the FTC should try to put a stop to this. AWS should not be permitted to effectively subsidize its and its partners’ services over outside competitors.
(And the US Government should never have accepted cloud deals with excessive egress costs. Part of the bidding process should have been a requirement for networking outside the winning provider to be priced competitively with internal networking)