A stratification system with a governing elite - that is, few leaders who broadly hold the power of society is called a (n) :

I believe the answer is: an elite-mass dichotomy system

Currently, almost all western civilisations took an elite-mass dichotomy system as our governing method.

In this system, the mobility within the government structure is very limited and all the people who can held middle to upper position in the government are only the ones that have good relationship with the top people.