https://www.polygon.com/2019/1/25/18197166/metroid-prime-4-delay-reboot-retro-studios-nintendo-switch
Work on the project has been reset, but is now in the hands of the organization behind the previous three titles.
A couple of things are worth mentioning:
1: this kind of honesty from a game company is not common, but despite the setback, the future looks promising.
2: However, the Metroid Prime team is largely disbanded from Retro Studios.
On one hand, I wonder what the original idea they went with would have looked like, but on the other I'm ok with this (despite most of the original staff from the Metroid Prime Trilogy no longer working there))
Maybe they did that because those companies were just sitting on their hands.