For that you need a very centralized VCS, not a decentralized one. Perforce allows you to lock a file so everybody else cannot make edits to it. If they implemented more fine-grained locking within files, or added warnings to other users trying to check them out for edits, they'd be just where you want a VCS to be.

How, or better yet, why would Git warn you about a potential conflict beforehand, when the use case is that everyone has a local clone of the repo and might be driving it towards different directions? You are just supposed to pull commits from someone's local branch or push towards one, hence the wording. The fact that it makes sense to cooperate and work on the same direction, to avoid friction and pain, is just a natural accident that grows from the humans using it, but is not something ingrained in the design of the tool.

We're collectively just using Git for the silliest and simplest subset of its possibilities -a VCS with a central source of truth-, while bearing the burden of complexity that comes with a tool designed for distributed workloads.