I think the main issue was he used Nintendo owned tools and libraries to make his game instead of the GPL ones, making the release of the port dependent on Nintendo's approval too. I guess even Valve didn't want to deal with their lawyers.
In principle he could use alternative tools, like libdragon, but he said even if he did that it was unlikely Valve would permit it, as Nintendo would still be antagonized somehow. And Valve it seems wants to improve their relationship with Nintendo (See: Valve blocked Dolphin on steam, and took down a video showing yuzu installed on the steam deck).
It's an interesting question of comparison actually. Valve run the world's biggest videogame ecommerce platform, for PCs only (including handheld PCs like steam deck). Nintendo run a comparably large videogame ecommerce platform, but only for their two hardware platforms: switch and switch 2. Just roughly based on hardware sales, seems to be roundabout the same audience size. Nintendo maybe comes ahead because they're well established in the hardware space (Valve is trying to close the distance), and of course far, far away in terms of 1st party game development - Valve has, what, 8 games? All phenomenal, but nothing compared to Nintendo's library.
Does Valve even make games anymore? The only thing of note they've done since like 2020 is put a fresh coat of paint on CounterStrike. Which still counts of course but it feels like they are REALLY coasting on the reputation of games that came out 20+ years ago.
Valve's working on Deadlock, an FPS / MOBA. It's very polished, but in early access right now. Based on what I've seen when I tried playing it, and just what I hear in the gaming sphere, it'll probably be a decade-defining multiplayer game once it's done, like TF2 or CSGO both are.
They definitely coast, but when they do release something, it's always phenomenal. I do wish they'd make more games, though.
If I recall correctly, there was also the issue that a Nintendo 64 ROM of their game would be fundamentally incompatible with Steam, which (as many forget) is technically their DRM solution. I could be wrong, of course.
You are free to publish any ROM to any system, it's a basic right against both monopolies and freedom of speech restrictions. What you can't do is to ilegally pull propietary dependencies without permission.
The problem I'm pointing out is that it's a work based on a Valve property that fundamentally cannot be tied to the DRM because it's "just" a ROM.
I believe this came up when the creator was talking about libdragon-- Valve has been more forgiving of other games like Hunt Down the Freeman and whatnot because they're native executables with the Steam DRM, which video games based on Valve properties necessarily must have. Portal 64 simply cannot do this, because Steam is not a Nintendo 64 application.
