Earlier quoted context omitted.
It's entirely possible the move to Azure has made the availability problems worse. Dedicated hardware is much more predictable than cloud. "Let's not move to Azure and instead buy a few more racks" was likely a decision beyond the pay grade of github's management.
Azure is easily the least reliable and least secure of the 3 hyperscalers, which is crazy because GCP was an also-ran underdog not that long ago.
But that doesn't matter because the kind of person that buys Azure, just like the kind of person that buys MS Teams, is entirely driven by price and does not care about anything else.