Most developers are working on a codebase where they did not personally write that "void main(...)" boilerplate! Someone else did all the initial scaffolding, they joined the team years later, and they're adding new feature "X".
In terms of productivity, all of those things you listed as negatives due to the mental load they impose are absolutely essential for this scenario of a team member joining and having to modify a large code base. Scopes, lifetimes, classes, interfaces, etc... are the levers for the mind that enable teams to work together successfully.
