Plus a rather clear lack of investment into improving it / retaining their talent / etc, yeah: https://damrnelson.github.io/github-historical-uptime/

Anecdotally: at work I saw quite a lot of github-uptime-related issues, and because they're the central host for everything they become *cough* load bearing for a huge amount of the company. Stability and performance has been dramatically worse than the self-hosted phabricator+gitolite before it.