Tooie is much more intensive than DK 64, with the game frequently making use of more advanced lighting techniques and large environments due to being an extremely late N64 game, even emulation up until somewhat recently had a lot of problems getting the game to fully work, so Nintendo might not even see it as worth it trying to get Tooie to run.
Tooie was heavily gimped on N64 hardware (or rather ungimped on xbox I guess) in other ways besides framerate as well, it's genuinely the worst version of the game. Kazooie's N64 version is fine, but playing either without the quality of life stuff the Xbox versions introduced is hard to adjust to.