However their revenues almost entirely comes from the new and not the old. Games don't go into syndication and get tv reruns. They are kept alive by the emulation community and I would argue it builds support for Nintendo's IP rather than do them damage. I have a kid whose first exposure to Metroid was Metroid Dread which he loved. We have a Wii but it is struggling a bit and he is playing through the Prime trilogy on Dolphin. No question he is going to go nuts when Nintendo release Prime 4. Cheap marketing.
I have been tempted to rip our Switch games to run on Yuzu but to be honest the Switch (we have 3 in the house) is just an ideal platform for these games and playing on a PC is going to be a worse experience in almost every way. The story is very different with older platforms. These will be history soon without emulation.