I think its actually because GitHub isn't solely running on Azure. They are currently using a mix of on prem, AWS, and Azure. The Azure migration has been a challenge with Azure running into capacity issues due to AI load.

to be fair all CI providers I've had the pleasure of working with have gnarly performance profiles for the boxes they provide.

I don't think it's out of malice, but I do feel uncomfortable with the fact that the people who sell me the CI coordination software also sell me the minutes for the boxes that run the CI software. There's _some_ alignment of interests but not as much as I would want!

It's not Azure as much as self-hosted runners are basement bin servers on clearly massively oversubscribed machines.