Wow! Sounds like a business major question.
Of course the military is a business...but it is not one based on making money, it is based on spending money. It generates no income, produces no product, but it does provide a service...so it is more of a service industry.
The proficiency of soldiers...(although only the Army are soldiers...I was a Sailor and the Navy is still military too.) Well proficiency is very high. Each branch of the military invest large amounts of money in educating and training the members. Each member is a technical expert in their field. While it may take years to gain a high level of proficiency, the younger an junior members are still preforming task with a high level of responsibility. The level of responsibility increases as the member gains more experience and advances.
The military operates with in a budget that is determined by congress. Revinue is generated through taxation. So when taxes are raised it has an effect on the ecconomy. Further there is also an effect when base closures happen. Jobs are lost. So while the defense budget may save money on closing an Army base in Arazona. All the small busnesses (dry cleaning, car dealers, resturaunts, retailers, and the like) will loose income from the loss of patrons. Some of the busnesses go out of busness and there is a loss of jobs.
When a new base opens or re-alings some new busness open up. Defence contractors (privatly owned busness even large scale such as Bowing and Lockheed Martin) gain more busness when dealing with the military. Creating more jobs...so the ecconomy will increase in that area due to increased money comming in. New homes and housing devopment and schools are also effected.
I haven't even mentioned the National Defense part. It is obvious that the main goal of the military it to protect national interests. Both domestic and foreign threats are guarded. We must be villigant as to the way of the world and that we do have enimies whether we care to acklowge them or not. We have to stand ready to prevent an invasion or to deploy overseas to protect our interests.