Not all MO shuls have staffs.
However MO shuls and Charedi shuls are generally set up different. In Charedi Shuls , the shul is the Rabbi’s. He owns the shul, He owns the property and raised his own money to build it. and can make the rules. He answers to nobody. Usually in MO shuls, they are run by a board of directors and the Shul is owned by a non-profit corproation that owns the shul and pays the Rabbi. The Rabbi answers to the board of directors and they can remove him if need be, they also gurantee his salary , that he will get what is promised .