I think it's just circumstances. MvDK series never lost their developer. Games just stopped being made for a while. Makes perfect sense for NST to do it, same goes for IS and TTYD. Square-Enix probably has say in Super Mario RPG. I think when they can easily get original developers/staff on board they do it, but it's not a requirement. Advance Wars Reboot was a different developer in Wayforward. Link's Awakening was by Grezzo. Samus Returns by MercurySteam.
Then there's also ports/remasters. Sometimes they're done by the original developers (Retro porting Tropical Freeze to Switch) and sometimes it's handed off to a different studio for most of the work (Monster Games porting Returns to 3DS). Wind Waker HD was mostly done internally while TP HD and SS HD were mostly by Tantalus Media.
Honestly the biggest reason I think there isn't a DK64 Remake in the works is Grant Kirkhope. He's still vocal to this day about not being credited for the DK Rap in the Mario Movie. Nintendo definitely would have had him on board yet he can discuss freely about DK and DK64 in particular. I feel like that shouldn't be the case if there was a DK64 project that existed.
It is worth pointing that Advance Wars had some staff from Intelligent Systems supervising it as JazzyFuture pointed above. Likewise Samus Returns had direct involvement from people who worked on prior 2D Metroid games like Sakamoto and Hosokawa. So in a way I'd say those games fit in within what I'm talking about.
Yeah, Dinoman is 100% correct. There's clear preference at Nintendo for re-releases to either be handled at their original team, or for original staff to oversee the project:
- Advance Wars: supervised by Intelligent Systems
- all Zelda remasters were produced by EPD3, the Zelda team, and had EPD staff attached
- ditto for Samus Returns, which had the Metroid staff at EPD7 in charge
(To be clear: "produced" does not mean "developed" - it's the language used to indicate who is in overall control of a Nintendo-published project)
By and large, Nintendo tap the original staff or team in some capacity. As has already been established, that includes the Another Code remakes, where the original studio was defunct but senior staff from the games were at Arc System Works. Who would produce and take charge of that hypothetical remake is an important question, because it's the board of producers at EPD who decide who does what and which things get made. Right now there's no clear advocate for Donkey Kong 64 to get remade, not least because we don't really know who will be in charge of DK as a franchise. Zelda has a clear production structure and management group at Nintendo who remain in charge of Tantalus and Grezzo's work on the franchise; DK has no equivalent.
And, as I've also said, it's not just Donkey Kong 64 missing from NSO. A whole bunch of DK franchise titles haven't made it to NSO:
- Donkey Kong Junior Maths
- Donkey Kong Land
- Donkey Kong Land 2
- Donkey Kong Land 3
- Donkey Kong (1994)
- Donkey Kong 64
- Diddy Kong Racing (seems fair game for NSO)
- DK: King of Swing
- Color and Advance ports of DKC
That's quite the list. Sure, a bunch are the handheld titles, but it's bizarre that after more than a year, not
one handheld DK game has made it to NSO, yet Mario, Zelda, Kirby, Metroid even Pokemon (in the case of GB) are represented in the handheld selection on NSO. Some of those DK titles missing wouldn't be all that odd, but
all of the possible handheld titles not showing up yet really is strange.
I think we might get a big DK NSO update, perhaps timed around the theme park opening. Maybe Rare's titles from the franchise: the DK land trilogy for the base tier, DK64 and Diddy Kong Racing for the Expansion Pack.