They are not using Docker at runtime for their services. Every company uses Docker for builds unless they have a particular cost or ethos they're avoiding and purely using Linux/podman/buildah/et al.

Thinking about it a little further, though, I believe Rancher Desktop has come a long way and may be eating market share.

I just never felt the need for it. I'm not saying it's bad (I really don't know), it's just one of these things that solve problems I don't have.

Most companies I’ve seen from the inside were using containerd or crio.

There are more secure alternatives. Are you sure those you listed actually use it on the servers? I would guess that at least Spotify and Netflix uses some other container runtime than Docker on their production servers.

For a long time Docker was helpful and opened exposed ports on the firewall. So you wanted to access your redis ports locally and exposed it on the container? Now everything in there is accessible on the open internet.

I believe they've fixed it but I haven't used Docker in years so I wouldn't know.