The problem is asymmetry along two axes. The first, information asymmetry. The person holding the code (the lone developer with an old floppy disk stored in th

The problem is asymmetry along two axes. The first, information asymmetry. The person holding the code (the lone developer with an old floppy disk stored in the attic) has no idea who the owner might be. The actual owner is well aware of what they own. That could be resolved by a DMCA takedown notice, yes. Alas, there's usually also financial asymmetry. And as an individual, the potential costs of a copyright lawsuit are not something you want to face. As a larger company, it's just part of your normal expenses - especially if your business model is "accumulate IP"