You're mixing up preservation with distribution. Nintendo preserves their games. That's how they were able to release an almost 30 year old incomplete game by the name of starfox 2. 

Nintendo is probably one of the best at preserving their old code, actually. They just don't distribute that code to the masses. In fact, rumor has it, they have the source code and/or a final ROM for every game that has ever released on any of their consoles.

Nintendo might have a widescale preservation effort, given that they released Star Fox 2 and an international release of Mother both in the 2010s.

The problem is that Nintendo has so many of their games in a vault it seems and is too stubborn to release them. With the impending closure of the 3DS and Wii U eShops, we'll only have NSO Online versions of NES, SNES, and N64 games. And they are not exhaustive collections, especially the N64. GB and GBA games are heavily rumored, and I hope it's true. And it's past time for GameCube software re-releases. That should've happened in the early days of the Wii U, and we're nearly a decade past then.

Good point. A lot of Japanese developers in the 90s didn't preserve their games. They would delete them to make room for new games.  SEGA was one of these developers, they no longer have the code for Panzer Dragoon Saga for example. Capcom threw out the code to Okami and Ready at Dawn has to basically recreate the game. Every version of Okami played on modern platforms is the RoD recronstuction version of the game. I am only guessing here but that maybe why every Sonic Advenure port is based on the very different Gamecube version. It made a lot of changes. I think Falcom almost did a few years ago until fans made a huge fuss.

A bit late to the party. The community already did this decades ago.
The only thing of additional value would be the preservation of the source code and assets so that they can be recompiled or remastered for newer platforms. But that has nothing to do with game preservation, it is more like game restoration.

I'm not sure how I'm going to sleep at night knowing I can't watch a random silent movie nor can I play satellite zelda.  

I guess I'll have to play elden, triangle and forbidden west.  Kind of sucks.  I bet satellite zelda was something.

Joking aside, I love how gamers feel they are entitled part owners of IP who should have a say on what developers do or don't do.

I couldn't care less about preservation of every damn 40-50 year old game that most people already forgot about and half the people who played it back then already are already dead. Only the most relevant and influential games from the 70s and 80s are worth a damn nowadays, proven even more by how most people reacted to all of those irrelevant NES games that Nintendo added to NSO that most people never heard of. Nobody cares about those games.
Most of those 670 lost games no one would have ever played again or cared about anyway if some archive still had a copy.

Throwing out game code is stupid obviously, since then publishers can't just rerelease games like SE is doing right now with many of their 90s games. But it's in no way the publisher's obligation to preserve their games. It's just smarter to do that, because it can make them money decades down the line.
I don't get the obsession with playing original versions of certain games if remasters and remakes are almost always better in most ways. Nostalgia plays a big role but sometimes it's just unreasonable.

That all said, Nintendo is already is preserving all of their games and most of them might end up seeing the light of day eventually... or not.

Games are an art form and we usually care about preserving art. Museums exist with that goal. Now, not everyone cares about old art, but overall it is an important part of our cultural history.

We don't typically preserve every drawing ever made in art...  just the influential pieces....  I agree that preserving key influential games is cool, but as somebody else stated 95% of old games are meh and don't need to be treated as Starry Night.  And the influential games are well preserved and have been released many times over on many systems.  

You have no idea.

An entire batch of historians is freaking out whenever a game is becoming unplayable for whatever reason and the code isn't properly preserved. They are fighting for years to force Video game companies to safeguard the code for future generations, with little avail so far.

They are also behind the archive.org DOS games page where you can download and play old DOS games in your browser in an effort to preserve DOS games:

https://archive.org/details/softwarelibrary_msdos_games

Like I said, I don't personally get that.  And I staunchly believe 'forcing' a company to preserve code is wrong.  It is their code.  They can do whatever they want with the code.  Nintendo (or anybody else) doesn't owe their IP to others.  People feel far too entitled.  My wife is an artist...  she can destroy her art anytime she wants, it is her property.  We don't own other people's property because reasons.