[ghaff]

The history of software licensing is sort of interesting. I had occasion to dive into it a year or so ago for a book and it seems to have been institutionalized with the IBM/360 because 1.) IBM was feeling pressure to sell software independent of hardware for antitrust reasons and 2.) All of the existing IP protection mechanisms seemed pretty iffy at the time.

[kmeisthax]

Software is one of the key aspects of the history of copyright maximalism, too. If you strictly applied the utility rule, software would only be patentable, not copyrightable. However, CONTU made a big mistake and convinced Congress to grant software copyright, which created a whole bunch of unanswered legal questions that are only now getting resolution through judicial legislation[0].

A decade and change later when Intel started asking for hardware copyright[1], Congress actually realized their mistake and created a sui generis right for integrated circuit designs ("maskwork rights"). We never complain about maskwork cases because they are incredibly limited, have a 10 year lifespan, and basically only cover direct copying. Software would have been no different had Congress not made the mistake of handing the full enchilada of copyright monopoly protection - including all those pesky questions about derivative works - to software companies.

[0] e.g. is linking infringement? can you copyright interfaces?

[1] Fun fact: before this, it was entirely legal to X-ray chips and reproduce them. In fact, the NES famously shipped with a bootleg 6502 that only had decimal mode missing because that was the only thing MOS could patent.