The database would also go bad within days (hours?) each time they did one too once Nintendo logged large numbers of different IPs downloading stuff at the same time. It would cost insane amounts of money and stop working almost right away, then someone would have to spend an insane amount of money yet again and again and again and again... Even if there were a bunch of donor IDs, it wouldn't take very long for virtually the entire database to go bad. On the other hand, if they don't give away their IDs and "sanitize" the files before sharing Nintendo can't tell where they came from and can't realistically ban. It's the same thing as with the Switch. It simply is not viable. Period.
Meanwhile there are CIAs all over the web that people can easily search and find (and even that one site with the weird name as if they were CD-ROM images when they obviously are not which has them all easily accessible to everyone) which make all this jumping through hoops wildly unnecessary and silly. This is viable and even downright easy. Besides, we don't talk about "warez" (geez, I guess no one uses that word anymore now?) here. Since you are just doing legal backups of stuff you already own, of course, you can just image your cartridges and convert those images to CIA installers so you can safely store the cartridges away. :-P