You and burmingdoom missed my point entirely.
I’m not saying retained value is good for future selling. I’m saying because they retain value for longer you don’t have to feel as bad for buying close to release that if you waited a little while it would plummet in price (allowing you to buy it for less) as is the case with Sony/MS releases typically after a couple month even.
Buying close to release has nothing to do with value- anybody with even the slightest bit of experience shopping for games knows you save by waiting, every time. Buying at/close to release is about relevance. The Shadow of the Colossus remake was a huge deal- 5 months ago. Far Cry 5, God of War, Detroit: Become Human- all big releases with lots of conversation, jokes, memes- also all irrelevant now. When you buy early, you're basically buying into that community, to be part of that discussion, to be the person those who buy later (by choice or necessity) go to when they want to ask which game is really worth their money. This means that, if you're not going to play a game at release, or if you don't typically join in the discourse, it can feel really foolish to buy early- you're not getting anything out of it.
It's easier to pick up a Switch game for full price later becuase, quite simply, very few Nintendo games get that kind of saturation into gaming culture. Breath of the Wild did it, but that's... that's kind of it. Super Mario Odyssey got attention, but not to the same level. And I don't see people whipping themselves into a frenzy over Octopath Traveler's impending release- it's about the same dull roar it's had for its whole pre-release run.
That's the trick- Nintendo's relevance is fairly consistent these days. It's timeless. There's no flash-in-the-pan popularity you have to catch early or miss entirely. It makes just as much sense to analyze or joke about Super Mario World for SNES as for Odyssey. You know that, whenever you buy in, there's a community waiting for you, if & when you're ready to join it. It's like being childless & buying a couple Disney movies for if your friends with kids stop by- Hotel Transylvania 3 might be 'in' now, but they won't care in 3 months & you'll have to worry about them trashing your stuff out of boredom. On the other hand- damn near everyone likes The Lion King, including adults- you may even watch it on your own.
In short- Nintendo is like Disney, in that they can get away with things their competition simply can't do.