NewYuzuPiracy

Unfortunately, Nintendo has some decent counterarguments for those defenses.

1. 17 USC §1201 (a)(2)(B) can be left up for interpretation around its phrasing. If you interpret the condition to meet the criteria being Yuzu must not serve a commercially significant purpose other than to facilitate circumvention of DRM, that actually works against Yuzu. The emulator itself serves no commercial purpose, which suggests it has no reason to exist other than to circumvent technological measures.

2. For as much as Nintendo hates third-party, unlicensed peripherals, they could point to the 8bitdo adapter and plethora of disability-friendly Xbox/PS5 controllers to weaken that argument. If the primary purpose of Yuzu was to fill a gap in accessibility, Nintendo could argue that Yuzu would have stopped development once other options became available.

3. 17 USC §1201 (f)(1) only applies to (a)(1)(A). That protects the developers in creating the emulator, but Nintendo's lawyers would remind the court that they're suing under (a)(2), which also includes distribution of circumvention tools.

It gets even more bleak.

4. Nintendo could demonstrate Yuzu fulfills (a)(2)(C)—the marketing of the product with the knowledge that it's used for circumvention—by referring to Yuzu's own documentation on its wiki and setup guide instructing users that they will need to dump and use prod.keys to play games.

5. The last criterion needed is (a)(2)(A)—which is that Yuzu was primarily produced to circumvent DRM. Yuzu's documentation and guide do not work in its favor, and the preservation/interoperability argument is weakened by the fact that the console is still readily available in retail. There's a good chance they can't even successfully argue it was created for development purposes. They would need to have a stronger argument than Nintendo's lawyers, and it's going to be really difficult to claim it was made to make Switch development/debugging more accessible than Nintendo's official devkit when they've never (for obvious reasons) had access to the official devkit or went through the process of applying for one.

If it goes to court, Yuzu would need some really deep pockets, good lawyers, and a technologically competent judge. I hate to say it, but the most likely outcome, in my opinion, is a settlement giving Nintendo exactly what they want.

I would love to see the EFF or some philanthropic multimillionaires bankroll Yuzu throughout this and set a precedent in their favor, but like you said, it seems way less realistic.