I think the problem is people think tend to conflate 'preservation' with 'publicly available' when something doesn't have to be made available in order for it to be preserved. I know this a bit of a morbid example, but the six minute audio recording from the fatal bear attack on Timothy Treadwell and his girlfriend is preserved in a bank vault without having been publicly released. (And yes I know 'recording of someone being attacked and killed by a bear' is not in the same league as 'video game' but it's the first example I could think of)
I have much negative to say about Nintendo, but I'm of firm conviction that they're excellent when it comes to archival, especially when you compare the rest of the industry losing their compilers or source codes and whatnot, which is generally unheard of when it's Nintendo (worst I can think of is Donkey Kong Country shenanigans... which isn't a mistake from Nintendo). I think when people mean preservation, it means accessibility with legacy content, and that's what Nintendo is bad at doing.
not everyone is morally okay with or wants to pursue piracy as their first option, as well
some people would prefer legal purchases even if illegal obtaining is an option, there's a reason mother 3 localization still gets traction. like, yeah, it's an option, but it shouldn't necessarily be the only option when it's an active downgrade from before where gb/gba games and other nes/snes/n64 games were available legally on modern systems and now just. aren't.
additionally it's entirely probable obscure eshop-original games didn't get uploaded to the internet at some point. stuff still falls through the cracks, after all.
I pirate stuff, but yeah, almost every video game I've pirated, I've already bought (Sims is a glaring exception though I'd spend money on it if the costs weren't so prohibitive AND it didn't require an EA account and another game launching client, AND that I do not trust EA as a publisher even though Maxis as a company I like a lot). I generally prefer buying over pirating, though what lies at the heart of it is convenience to be quite honest. There's a satisfaction owning the physical or even digital copy of the game, using your own money to acquire something, it's not really there when you download a game. Also, downloading stuff requires jumping through several hoops and always taking a risk with your computer and requires identifying scam sites (and you're bound to come across some weirdass obscure foreign file hosters that almost always seem to throttle your download speeds unless you subscribe to something you otherwise won't use), using an adblocker, and using an antivirus.
The thing is though, I don't want people to go through illegal means to get something they want,
especially risking computer security and downloading potentially bad files or browsing shady websites. I wish Nintendo cared about the safety of their customers that they don't have to go through this just to enjoy Nintendo's products. Krita, a free content-full art program, I recall, explicitly cut to the chase about the real issue about artists doing piracy and other illegal means to be able to art, which was pretty refreshing to see validating acknowledgement about why some people do illegal things. Either way, correct, and I'm confident to say MOST people would buy rather than pirate.
Anyhow this cancellation of the service sometimes gets me worried. What if Steam shuts down one day? I don't see it happening in any foreseeable future since Steam makes enough money, but this situation should highlight the fragility of digital storefronts. People also seem too comfortable that physical copy is somehow more protected, but no... you still require a means to play them, which hardware failures exist (scratched CDs, failing disk drives, power failures, etc) and repair services for that hardware isn't always going to be available through official means. I still think digital files and a means to use them AND storing them in constant copies and backups, as long as the means to use them continue to be able to be compiled, maintained, ran in official PC OSes and infrastructure whatnot) will outlast physical copy. It just reminds me how fragile digital content can be despite the huge benefit of instant and easy duplication, but I guess that's another discussion.
Oh and I'd like to add about Internet uploading... there's no guarantee any given game will even run well on emulator either. Final Fantasy Crystal Chronicles remains pretty elusive to play for a while (the Switch port also stinks) despite all means of emulation technically existing. There's just a serious save problem early in the game that you can't progress without save states. I think it was fixed in subsequent updates, but there probably remains several GCN/Wii games that have serious issues. Mario games from Camelot also tend to have visual emulation issues.