Is it? I don't think Apple would sell you one right now. I kinda wish someone got sued over pirating abandonware, the company would most likely lose, and that would set a great precedent once and for all.
I'm a lawyer, but this is my meaningless drivel. It's not legal advice. You shouldn't listen to me. In fact, you shouldn't listen to anyone on HN about legal issues, ever. The copyright discussions here quickly devolve into complete nonsense. I've done software copyright for a long time, but I sometimes have to read posts five times to kind-of-sort-of-think I know what they're trying to argue. And it's almost always wrong.
(grishka, this is not an attack on you at all. Your post is fine.)
(I'm not from US, and I only have a very vague idea about how the US legal system works)
Buy it second hand on eBay or craigslist or whatever, I guess. Or reimplement it.
Of course neither of these are good options, just the "technically legal" way.
But that's not really related to US legal system or 'western countries', the core principles of copyright are the same almost universally across the globe - here's https://en.wikipedia.org/wiki/Berne_Convention#/media/File:B... a map of Berne convention signatories, there are just a few countries where that doesn't apply. The strictness and likelihood of enforcement of those laws varies a lot, though.
Note that under the law of some countries the right not to distribute a copyrighted work is viewed as a sort of natural or "moral" right to control one's creation. The US doesn't generally take that view; we think of copyright and copyright damages mostly in economic terms. Thus, if your "pirating" isn't actually doing economic harm to the rightsholder, you're somewhat unlikely to owe massive damages. Countries with more moralistic copyright regimes may have stiffer penalties in your scenario.
You might have some pity for Apple in your scenario (I do) because the law strongly encourages rights holders to bring a lawsuit in order to protect their rights. It's a use-it-or-you-might-lose-it-to-some-unknown-extent scenario, and lawyers and companies hate uncertainty. This can lead companies sue for copyright violations even when they don't really care. For example, a book's and publishing house probably don't care about a fanfiction blog. They may even like fanfiction because it's grassroots promotion of their product. But they may still feel forced to sue to stop fanfiction so that their rights aren't questioned the next time they need to sue, e.g., a bootlegger that's passing off unlicensed copies of their product as the real thing on Amazon.
On a more positive note, I like TFA because it highlights a company that did The Right Thing. WordPerfect made its Mac product (WordPerfect 3.5e) freely available when it stopped selling Mac software. WordPerfect 3.5e was released in a responsible way too (IIRC) by creating a special freeware license, which minimized the risk of losing the right to enforce the copyright in the future. Open source would've been even better, but there are many good reasons why businesses wouldn't want to do that where a product integrates third-party-licensed code (WordPerfect 3.5e for the Mac does, according to its "About" screen) or if the product is still being sold commercially on other platforms. The WordPerfect 3.5e approach won't satisfy open source fundamentalists, but it solves the problem you identify, and it does it with minimal legal risk. Keep it in mind and tell your lawyers or managers about it if you're ever faced with the question of what to do with your company's unsupported commercial software.
(Again, not legal advice, random online ramblings, don't listen to me or anyone else who posts on internet fora.)
[0] https://download.info.apple.com/Apple_Support_Area/Apple_Sof...
Again, probably nobody will arrest you for this, but nobody's likely to arrest you for conventional piracy either.
Unfortunately as a result, they're packaged in self mounting Disk Copy images, so you'll need an old mac to unpack them. It's possible someone has developed a tool to extract regular disk images from these files by now.