People and animals have different immune systems and metabolisms. Many functions are exactly the same, many are similar and some are completely different. The immunity elicited by the rabies vaccine lasts a shorter period of time in dogs and cats than it does in humans.

There have been studies done to try to extend the period between boosters, but length of protective immunity is variable and some animals may not be covered for rabies if the interval is extended, so they have not yet changed it

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7088826/

Also, some vaccines require yearly boosters (inactivated/killed) because they don't generate as strong or as lasting of an immune response. The active or live vaccines produce longer-lasting immunity and are usually given every three years as per the current vaccination guidelines.