I like to believe most people are sufficiently with-the-plot to appreciate that there is a difference between a "container", "container runtime", "container orchestration" and "docker".
No one is seriously confused about "using docker" meaning, oh hey, I run my containers on kubernetes. I have literally never met someone who was confused about this. I suppose some people just stop at "I use docker" and don't know what that means when it hits production... but I'm skeptical they actually think a copy of docker is running out there in prod.
...but to be fair, the parent comment did say that running "docker containers" was mainstream; and fair enough.
My point was running containers using docker most certainly is not.