I think that is impossible that developers becomes as DevOps in all teamworks. Remember, DevOps (not just culture) is about how you could resolve 2 problems with 1 solutions and this background is not collected while you are coding. As DevOps or SRE there are a lot of knowledge about platforms, protocols, practices, tools, and so on.

I mean, what should happen if you try to move SRE or a DevOps engineer as a professional developer? Obviously would be a frustrating and complex what to improve the software.

Regards and nice article. :P