I mean you answered your own question really, development restarted from scratch. Whatever Retro Studios had was more or less a proof of concept that Nintendo liked, so they have to build it out. Assuming development is proceeding smoothly, we could potentially see it next year I think but who really knows.
It's been a log wait, but it has been worth it. When the project was restarted, it was handed off to Retro Studios, who are the ones responsible for Prime 1, 2, and 3. I am actually happy hearing they will now be doing 4.
At this point, I think the long wait is more for our benefit in ensuring the game is a masterpiece. Great visuals, worlds/environments to explore, story, puzzles, and soundtrack.
I'm guessing the pandemic was a big hit to development.
While plenty of the big AAA titles on Playstation and Xbox tend to have entire international teams constantly figuring out ways to work through the pandemic, I'm pretty sure Nintendo is fairly localized to Japan, where they had stricter lockdowns. Similarly, I'm willing to bet that the original window for Breath of the Wild 2 was probably earlier than 2022 as well.
MP4 has had a rough development history. First Retro was working on it, and then it started again with a team assembled by Nintendo that had people from Bandai, From Software.... etc, and now it's back in Retro's hand. Also along the years, lots of people that worked on the original Trilogy left and started their own companies. I think the expectation and the Switch's limited hardware is what is holding MP4 back. Plus the last we heard, the game was being built on a custom version of the Cry Engine which is not the easiest engine. There is a shimmer of hope that more new experienced people have been hired recently.
Only Metroid Prime game I’ve played was Hunters on the DS. Waiting for a prime Trilogy to come out, so I don’t mind the wait. Just hoping it comes out a while before MP4 so I have time to beat the trilogy.
the new working title is Metroid Prime 4: Vaporware
but seriously, i highly doubt any dev has done any meaningful work on it. when it comes to nintendo ips i think we are all old enough to translate "wellll do u want a rushed mess (let's pretend patches and updates can't turn bad launches around at no extra price) or would you rather a decade for a loving masterpiece "because that never goes badly in this industry," said Square Enix? i mean just look at Metroid Dread, absolutely... mind blowing reward for my patience. demoness said sheepishly, rotating the sinner over the campfire.
but enough facetiousness. i love metroid and i'd buy the ip no matter how good the game is or isn't. not bad mounting the ip. but dread, a blatant asset saving measure, part returns 3ds 2, part retread of Fusion with a mechanic the past decade of indie games and AAA horror has done to death by now and the AI still isn't much more advanced for these 2D appetizer projects, which yeah, i understand you could reduce any game to "ashkually, you can say that bout anything" but that isn't my point. i play warriors games, i get the irony. the difference is that series doesn't have a history of something fresh each release and doesn't play the violin for a game in limbo. modern nintendo management being what it is--i wouldn't rationalize for a minute. until there is more than a dev placeholder, it's nothing, and by the time it is i don't see the game being relevant or able to hold up against even recent games.
any 28 year olds or in the age group feel me or nah? boys don't leave an angel lonely