Yooka's problem was that they had everybody who made Banjo EXCEPT the creator of Banjo; Greg Mayles directed all 5 Banjo games and is the only one of the old guard still at Rare.

Same reason Mighty No. 9 went to shit.

YL problem is that they made the exact same game they did decades ago, while not improving the genre,but because they had less money it was inferior. Mighty No. 9 went to shit because they over promised with the kick starter and because Inafume is not a game director (he is a designer and producer) he did not have the skills to save the game once it became apparent it was not good. As opposed to Iga, who actually also had a trouble production, but because he had directorial and programming experience was able to save his project by killing about half of the ports, focusing on the main game, booting everyone from development who was not good with Unreal Engine and putting them in another Project more suitable for their talents (that is how Inti Creates ended up making Bloodstained Curse of the Moon), then bringing other developers with experience in Unreal (such as Wayforward).