I thought it was way more than that. The sudden drop of Prime games and handing the franchise off to mercenaries makes it seem like Retro can't do it anymore.
Sudden drop? The Prime Trilogy had ended, Retro wanted to do something else, their Switch game is rumored to not even be Donkey Kong Country related but maybe something completely new. (Especially since that reboot didn't take as expected.)
It's not like Metroid is a major Nintendo franchise. The
entire series hasn't cracked 20 million sold. (edit: this is counting those "games" only Andy considers canon) The last three
console Zelda games alone have almost outsold the entire Metroid franchise. Only the NES game seriously cracked 2 million copies. The first Splatoon has more than doubled every Metroid game but the first and it was released on the Wii U ffs, the Switch sequel might destroy that number in a year.