I guess the DRM was strong enough for this product, it's past its shelf life now. Or is this a case of no one really wanting to pirate the game badly enough to put in the effort to crack it?
N64 game cracks were desirable even without emulation though. There had been "universal" carts (e.g. Doctor V64) that would enable running a game image on a retail console.
[1]https://en.wikipedia.org/wiki/UltraHLE [2]https://en.wikipedia.org/wiki/Banjo_Tooie