>reproducibility isn't just on your deployments, it's for development too
Absolutely. Adhoc configurations should be forbidden! It is easy to ensure dev env reproducibility when you run Linux. If you have config management your devs can have VMs that subscribe to the same exact configuration that the staging prod and dev environments have. They can literally have a deplpyment server in their machine, as a VM. Since the configuration is stored on a server and applied continuously, it is hard to screw it.
You can achieve this with Docker as well, if the arrangement is not too complex.
The problem, at least in my experience, comes when you start depending on several cloud native components where local emulations are always different from the real cloud env in tiny details that are going to screw the deploys over and over.