> Troubleshooting a working, in-motion system requires a different set of skills, in my experience, from writing and debugging code

I'm not convinced of this - or rather, if someone can't troubleshoot a system in motion, they're going to struggle to actually develop anything substantial. Debugging is a very underestimated skill of programming.

I think the conflation of "devops" is nothing to do with skills and everything to do with culture. When you have them as separate business units or teams it becomes adversarial: every deployment is a potential headache for Ops, so Ops try to prevent deployments or set up staging barriers to minimise this. Whereas developers may not appreciate the difficulties involved in deploying a large system vs the toy one they're developing on.