Where do most former military officers get jobs?

Defense contractors. Especially for those who earned senior ranks.

A reduction in grade carries with it an instantaneous revocation of a clearance, no clearance, no job in defense industries. (One of the more obnoxious things about the way Pentagon procurement works........ Retire from the Pentagon, get a job with the contractor you just assisted in getting the multi-million XYZ contract, and get your replacement to shift contracts your way)