Ideally you should not be seeing k8s at all in mission critical infrastructure in any tech company. I know few FAANGs that stay away from it.
EDIT: part of actions, codespaces and packages are not run on k8s, but 80% of github services are
That's really not the endorsement you think it is.
For example “users cannot resume code spaces created before the incident” sounds a lot more like an application level problem.