I'm conflicted on this one. Is it legal to download ROMs if I don't own a physical copy of the game?
To be honest, people who hold onto copyright for 20+ years and have no intention of supporting it, etc... are greedy little monsters. I could go on and on, but A: they don't support it anymore, B: they don't sell it C: they don't care even if you do own a physical copy
Given those 3 points, its best to treat nintendo like they treat their fans, which is to say, do what annoys them because they are constantly on their high horse. No one needs a 20Y+ copyright license, for anything electronic. This usually just enables the worst behavior on their end anyways, such as data mining, spying, built in malware basically and especially data collection so they can sell it for more money than the value of the physical copy itself.
So yeah, copyright infringement is meh, but as long as you aren't redistributaing for a price, I see zero reason this should be illegal given the above.
They will hold onto their rights for 70+ the life of the original author. Talk about a ponsi scheme.
However if you want to make safe, if you do download, don't share with anyone anything except where you found it.
That is probably the safest way to do this.