When you have a dozen developers working on the same project, doing the deployment yourself is a danger to the company.
How and why? There may come a point where it's worth segregating deployment from development, but I'm certain it's a long way north of a dozen.
Deployment is mostly-automated - put a note in our chat channel topic that you're deploying (or queue if someone else is already deploying), push a button to do a release and deploy as staging (and a small smoke test), do any manual testing (or investigation of logs etc. if something goes wrong), push another button to flip that deploy to be prod.
Any of the 12 devs can do this (and does, we each deploy our own features/stories), any of the 12 devs can make changes to the deployment scripting just like with any other code area (some will be more or less familiar with them, but that's true of any area of the codebase). Nothing unique about it, quite the opposite.
For my company, that would probably be a death blow.
I'm mostly in Ops and I often find myself getting handed something from less skilled developers to run in production. It's frustrating too.