The cost of egress traffic is a very good reason for many organizations to not fully migrate to a cloud provider anytime soon. And since, unlike with storage costs, there doesn't seem to be an actual reason (other than: it makes migrating to competitors cost-prohibitive in a subset of cases), that seems kind of... weird? Small example: an actual company I do some work for is in the business of delivering creative ass…
My theory: it forces third party services into the same cloud.
Suppose you use AWS and you want to pay a third party SaaS provider for some service involving moderate-to-large amounts of data. Here’s one of many examples:
https://www.snowflake.com/en/data-cloud/pricing-options/
And look at this remarkable choice: you get to pick AWS, Azure, or GCP! Snowflake is paying a lot of money to host on those clouds, and they’re passing those costs on to customers.
Snowflake is big. They have lots of engineers. They are obviously cloud-agnostic: they already support three clouds. It would surely be much cheaper to operate a physical facility, and they could plausibly offer better performance (because NVMe is amazing), and they could split the cost savings with customers. But they don’t, and my theory is that egress from customers to Snowflake would negate any cost savings, and the variable nature of the costs would scare away customers.
So my theory is that the ways that customers avoid egress fees makes the major clouds a lot of money. IMO regulators should take a very careful look at this, but it’s an excellent business decision on the parts of the clouds.