Copyrights are automatic now(have been for decades). Most companies don't even bother doing that, you only need to for statutory damages, and most smaller companies don't do that for every revision.
Automatic or not, the problem is when you run into a party who doesn't respect your piece of paper, e.g. China. You can sue for "damages", but it doesn't unsteal your codebase.
Copyrights are automatic now(have been for decades). Most companies don't even bother doing that, you only need to for statutory damages, and most smaller companies don't do that for every revision.
Automatic or not, the problem is when you run into a party who doesn't respect your piece of paper, e.g. China. You can sue for "damages", but it doesn't unsteal your codebase.