> Is there any language where you can just go:

Nothing prevents a map function to run in parallel.

There are other things that can happen in parallel, however - the whole instruction flow is reordered in the CPU before it is executed and if you have enough execution ports and enough in-flight instructions to keep them fed, you can accomplish a lot in a single clock cycle before your source code even needs to acknowledge that instructions don't happen exactly in the sequence they are written.