But the amount of compute needed to serve is not very high. It's all text. The amount of bandwidth and compute needed to serve a Netflix or YouTube is far far harder and they managed just fine.
they also aren't using azure. IDK what youtube is on, but netflix has actually faced their problems and found solutions (freebsd, mostly)
They should migrate to AWS.
Its webscale
Netflix and YouTube both built custom CDNs. Netflix uses AWS for control plane only.
Also, respectfully, you have no idea what you're talking about. "Just text" doesn't make it easy to solve. GitHub Actions aren't just text and take a lot of compute.