Before patents, copyright law, and all that, secrecy was the only way to stop people copying your stuff. That was kinda crappy, and people went to great lengths to obfuscate their IP, expending lots of effort on something that had no benefit for their customers / the world.

Intellectual property law changed that - it made it possible for people to openly disclose their inventions whilst maintaining control of them (normally with some conditions). It was a really, really good thing for society, as it dramatically increased the returns to "thinking work".

I can probably dig out a link if you're interested.

How is copyright / patents / IP making companies' code bases open to public or it's secrecy is not as guarded as before (as implied by your quote) ?

Especially since copyright predates software or you know computers.

Citation needed.