There is no reason consumers cannot demand this even though they haven’t. There is no reason the law cannot demand it even though it hasn’t.

The important part is that the idea exists and is common enough in OTHER situations. When you ask for it there will be people who know what this means and there is a whole industry of “we escrow your code for you” that can handle the details. If you make a new law you have plenty of examples to look at and so are much less likely to accidentally create some unintended consequence that is worse than the current situation.