Valve and Nintendo have no working relationship. There is an approximately 0% chance that Nintendo, as a game publisher, will ever publish on Steam. This is a pessimistic move by the legal department, nothing more.
The cost to build/maintain a competent platform is also not cheap even for the big boys like EA.
Otherwise everybody could just use Steam as advertising platform.
Of course I have no idea how contracts for big companies work
They changed their strat abt a decade ago.
If Nintendo ever exit the console market then we can have that conversation about Nintendo IP on Stream. But if that happens, and it is a massive IF, that’s not going to happen for a long time.
[0] - There were other Sega games published in 1995, but the examples I mention are titles specifically developed in house by Sega rather than titles by a 3rd party that they published.
[1] - Politely ignoring that whole NV1 debacle here, since it was in the end a very niche card.
I don't see there being a 0% chance (though admittedly a low one) that they bundle some of their back catalogue with an emulator and release the titles on PC (like Sega on Android/iOS).
If they think the value of those sales would exceed the value added to the switch of eg Mario kart 64 being exclusive, then it'd make sense.
(Again, from the perspective of Nintendo. It'd obviously be great if they released these things on different platforms from a user perspective)
Sony has shown that people are willing to pay $50-60 for games that are a few years old but newly released on PC. See God of War, Horizon, Spider-Man, and I think there were a few more too.