[rlpb]

Can you provide any evidence to support that claim?

Here's a report that suggests the exact opposite:

"Don't let the revenue numbers lead you to thinking Red Hat Enterprise Linux (RHEL) is more popular than Ubuntu. By The Cloud Market's Jan. 8, 2019 count of Amazon Web Services (AWS) instances, Ubuntu is used in 314,492 instances, more than any other operating system, while RHEL is used in 22,072 instances."

https://www.zdnet.com/article/inside-ubuntus-financials/

Disclosure: I work for Canonical, but as an engineer; I'm not in marketing or anything and that's not my job. But I do get the impression that Ubuntu is way ahead in general use in the cloud, and is also the generally used base for Docker images (I don't immediately see how to get that statistic out of Docker Hub). I didn't think this statement was controversial.

[jniedrauer]

A more apt comparison would be Ubuntu vs CentOS (and amazon linux and all the other repackaged RHELs). Ubuntu definitely has more market share, but the OP implied that it was "just the way things are done now" which is not true.

The last data seems to be about 3 years old, and Ubuntu was about 1.5-2x the CentOS/amazon linux share. I suspect that's changing with the release of amazon linux 2, but there's no data to back that up.

Amazon itself primarily uses a RHEL based distro, which is what I meant originally.