Not every IP can support a heavily practical attraction. Heavily detailed (animatronics) practical effects have limitations to their movement speed and, most critically, longevity. Most “classic” dark rides feature stilted, unnatural movement in a chaotic environment so that, if it does break down, it’s hard to notice.
As much as everyone wanted animatronics on MK, the franchise is all about bright, whimsical chaos at blinding speed. Animatronics would have, very likely, slowed the experience down. Worst yet, a down animatronic could cripple the ride experience completely.
The fact of the matter is, as the speed of the *experience* increases, the less feasible practical effects and animatronics are. Frankly, any practical effects in the “race” portion of MK is an astounding achievement.