This is a strange argument that I've heard repeated often: "repeal copyright and just treat it as an NDA". I personally would consider that
worse than the status quo.
NDA-based copyright-like ownership has three different problems:
- If the group of people with the software is large - like most mass-market works - enforcing the NDA will be absolutely impossible. Someone will leak, and that someone will not have the financial means to remunerate you for your subsequent loss of exclusive ownership. Making an example of them will not work. Once leaked, people will be able to legally republish without repercussion, so such NDAs are far weaker than even the weakest copyright.
- If the group of people with the software is small - like most specialized software - enforcing the NDA will be so successful that the software will effectively never enter the public domain (in both the intelligence and copyright lawyer sense of the word). Archival of old works will be impossible purely because the NDA did it's job too well. Such NDAs would be far stronger than even today's life+70 monster terms.
- In either case, traditional exceptions to copyright such as fair use, first sale, the merger doctrine, scene a faire, and so on will not apply. The NDA will prevent disclosure of even things that would not be considered copyrightable. Want to benchmark the software? Sorry, you can't, it's all under NDA - just take our performance claims as gospel.
The underlying problem is that copyright is supposed to be a bargain: the public agrees to respect a limited monopoly over publication of the work in exchange for creating a market that encourages more works to be made, as well as unlimited access to the work once the monopoly expires. In a sense, this bargain has been broken. Copyright owners lobbied for hilariously long ownership terms, right around the same time that individuals got access to commercial-grade publication tools that made piracy easy and interesting to do. "Just NDA everything" proposes abandoning the bargain entirely in favor of extremely authoritarian yet difficult to enforce controls on all works; something that we should not accept if we want to continue to have a market for works of mass culture.