Your world is very narrow and limited. Some devs also have to deal with customer provisioned HW infrastructure, with buggy interactions between HW/virtualization solutions that every 5 minutes duplicate all packets for a few seconds; with applications that interact with customer only onsite HW you only have remote access to via production deployment; with quirky virtualization like vmware stopping the vCPU on you for hundreds of ms if you load it too much which you'll not replicate locally; with things you can't predict you'll need to observe ahead of time, etc. And it does not involve editing any configs. It's just troubleshooting.
