I'm not sure this is really true, since copyright applies to distribution.

If you have a substantial amount of backend code (as with most SaaS projects) you're never actually distributing the code, and copyright is never at play. Computer generated artifacts are already in this boat and are protected by virtue of being trade secrets not by copyright.

This could maybe be true of shipping javascript to the browser, which presumably is not going to qualify as a trande secret, but I don't think that's where most companies derive value.