I guess i have to tell people some important stuff regarding "flash cells" technology and why for example a SNES or N64 module got such a supreme lifetime compared to modern "NAND cells" which is as well a flash-type storage.
I told already, even the NAND cells got different quality; so a very high quality one (for example the one used on a expensive PCIE 5.0 SSD but even inside a PS5 some high quality NAND is soldered on their PCB, which can life over 10 years without issues) may as well offer very good lifetime. A bad quality NAND on the other hand may offer a lifetime that short... it may completely die in a few years.
The Wii-U for example seems to use such "bad" NAND cells in many cases... and indeed... the liftetime of this storage is close to zero; in many cases it can die in just a few years... or short time after its warranty is over.
However... the flash cells used on a BIOS chip from a modern PC, even a smartphone got such a BIOS chip... those are basically more or less the same "type" of flash cells. This flash cell is not a NAND-cell, it is a NOR-cell.
NOR cells offer smaller storage, slower write speeds (not slower read speeds, it could even be higher) and of course higher costs but their lifetime compared to NAND is supreme. Other than that they offer almost the same "flash-able" memory.
However... on the SNES or N64 modules, which had a very low capacity of a few MB up to 64 MB (maximum, rarely used) it seems there was even EPROM (erasable programmable read only memory) involved (as far as i can say... the knowledge is very hard to be found... almost no one is writing about). A EPROM is NOT offering a flash-able memory in the same sense such as NOR or NAND-flash. However... a EPROM can last extremely long... no one can say how long it may last but... it can surely last just as long as any "physical disc". The disadvantage is simply the very low storage size and the very high costs (in relation of its size... of course). Just as i said, those consoles did have very low storage and it was working for them, thanks to a very minimalistic design and a OS that was not much more than a fragment of the "most critical kernel it actually needs in order to make nothing more than booting up a game", nothing else.
Nintendo, on the modern consoles (Wii and upward) simply did not care quality anymore. I would say the last Nintendo console offering very high quality was the Gamecube... any console after this one (i do not include handhelds now... it would get to complicated) is with way lower quality... on purpose... because Nintendo simply did not care anymore and the "demand" from the industry has changed toward "big data size, fast speed, low cost per GB and what else". In general... a console was more close than ever representing a actual PC with the same traits... strengths and weakness.
The Switch... it is very closely representing a actual "handheld": Gamers can get many of those on the market with very comparable technology in many cases... Nintendo is not offering "a supreme quality solution" anymore, just the a market demand of "a cheap and affordable portable system" and with a supreme marketing slogan... or name... such as "Switch and Steam"... if people hear it... they instantly have to buy it just because of its name, not because of its supreme quality. The true gain is simply the "supreme" Nintendo platform... not their hardware, at least not on the quality-term. The modern Nintendo basically is a "marketplace" such as any other marketplace... this is the raw truth, lacking some details now.
I would say... nowadays... everything is marketing, a launcher and a service... nothing else. It may not necessarily be "good data"... this is relative as everyone got a different taste, and absolutely it does not involve supreme quality hardware... this time is over for many years already.
The demand has "shifted" away into hardware that is at least able to surpass its warranty period... and able to hold as many of the "digital marketplace data" as possible... and it need a great name of course, so people know "what to buy" because i know.... hard to admit... most people are sheeps and dumb as nuts... i am sorry to be so direct and honest now, it may beat me down, biting me somewhere, at some point for sure.
Anyway, yes, as far as i can say (very little data available), a SNES or N64 was using a EPROM chip in order to store its game data... and this solution is... it can not be compared to NAND flash... it will outlast NAND by a mile... not fair even to compare it in the quality aspect.
No matter what, even NOS-flash cells would offer way more lifetime and can probably be good for dozens of years... but even this one was not "big enough" for the huge data demand anymore. So, indeed... Nintendo "skipped" the idea of using another flash or hard coded memory (EPROM is kinda hard coded). It is expensive and the data along with the general consumer demand has changed.
In general, any flash type (or even hardcoded) other than NAND is nowadays only used on certain firmware (BIOS, UEFI whatelse) of any computer device, because if this data is lost... the device is done and gone... not hard to tell. As for games.. no one really cares anymore if it is "done and gone" (the industry even may enjoy if someone is losing a game... so they can buy it NEW = win)... as a modern game is usually "consumed" short time after release and then patched up for many years until there are no bluescreens anymore... or in some cases not even patched up because the functionality was just "in order to provide something new that can at some point vanish itself like a oversized fart into the blue.... screen".
Long time ago... those "quality storage" was even used for game data... and thats why a SNES or N64 module can probably outlast almost anything.
Indeed, even NAND could offer more quality but then they will have to be build in another way... for example way bigger cells... which would increase the price a lot... and nowadays... people are usually nothing more than "consumers"... so as soon as a game has been consumed it can safely become lost... like a soft drink that may destroy some brain cells... i mean NAND cells... after. This is the entire idea of the "modern industry". If anyone is even caring for archiving games or making it "long lasting" it is either a certain platform... as long as it is commercially viable... or some "freaks" such as GOG gamers.
Another group are "retro (console) gamers"... those even are able to buy some "remaked" modules, for example here:
https://krikzz.com/
Of course such parts can still be gotten, mainly for industrial use... and indeed... some "retro lovers":
https://www.mouser.ch/c/semiconductors/memory-ics/eprom/?srsltid=AfmBOor85elOprYnHAnjrsjz9meS6fpKQv52TocaHAdpM2UkagCrrMou
I am NOT against big data, do not get me wrong now because it as well can offer some unique traits. In the same term i also do believe that small data and extreme quality storage is something many people could fall in love for.