Unfortunately, the myth about games becoming "abandonware" is pervasive. Before modern digital distribution, most games were pretty much only ever legitimately sold in boxes and when those went out of print it often appeared to mean the rights holders had abandoned their intellectual property or didn't care to use it any longer. There were several websites in the early 2000's dealing with the distribution of pirated games and other software that the proper rights holders didn't seem to want to sell or enforce their ownership upon. "Abandonware" was ALWAYS piracy, plain and simple. Just because no one was there to stop it from happening doesn't mean it was not intellectual property theft.
Now that rights holders can sell their products easily via digital distribution with little overhead (compared to printing discs and boxes that may or may not sell at all) it should be obvious, but many who were part of the "abandonware rings" or at least downloaded games that way are still stuck in that mindset. Just because no one is selling it doesn't mean it is "finders keepers". Even though there is a (US and EU?) law that says musical compositions become public property some 70 years after a composer's death unless another entity holds the rights, the idea that "abandonware" is a legal status is entirely fictional, a myth that grew in the early 2000's to justify software piracy of old games. I remember often hearing at that time that unless a software copyright is renewed for 10 years the game becomes public property or rather "abandonware". This is completely false.