Prime Series was developed by the remaining team of Iguana Entertainment which were responsible for Turok I and II (III was when they went downhill). When they reformed as Retro Studios, they were the perfect FPS team to revive the Metroid series to what it was known as today. I know Prime III wasn't as good but the truth was that Nintendo forced them to release it early. In fact, they did that to most of their franchises on the Wii namely Brawl (code was found for characters from melee that were omitted along with other characters that never made it) and Prime 3.
If Nintendo would rush those games to release knowing they could cash in on their name, why would they hire Team Ninja who just makes anime-based stuff? So they can cater to their home country. Why would they throw in anime-themed melodrama (look at the trailers)and make Samus look like a androgynous teenager? Personally I can't stand to look at that, its hideous and repulsive. Did anyone look how the combat works? You can't move in first person view!
Nintendo doesn't care for the Metroid series anymore. If they did, they would've let Retro flesh out Prime 3 and let them keep the rights to the series. Aside from that, anyone remember Metroid Dread, the real 2d sequel to the series? It was hinted in Prime 1. What happened to it? Nintendo is cashing in on its own franchises by doing remakes (as we saw from remaking pokemon games, brawl being just a few modes and characters better than melee, and a mario galaxy TWO) because they are afraid of going ahead in the story because it would mean more resources and furthering the plot to something solid. Heck, one can argue the Wii is a remake of the gamecube just marketed and hyped very well. I bought into it and stood by it for years but now its time i just stick with what doesn't fail, old games and PC.