The US military is a system that converts high school students (of varying capabilities) into soldiers and officers.
1. You start with propaganda: movies and video games that show the military in a positive light, encouraging a number of impressionable kids to join the military. I'm not against propaganda btw, but I understand how it works: the modern military spends a lot of money on Call of Duty esports for example, Twitch.tv recruitment, etc. etc. The goal is to make a positive first impression, usually through an entertainment venue (sports, video games, or movies)
2. You continue with explicit ROTC programs: where the high schoolers (or college-kids) can get their first real taste of military culture.
3. At actual recruitment: there are standardized tests that sort students off of their capabilities: finding a job that matches their skillsets.
4. You have a training program ("Boot Camp") that gives these recruits the skills they need to start their job.
5. You have a clear and well-understood ladder, organized by rank and pay-grade. Though its somewhat complex to outsiders, those within the military fully understand what they need to do to grow as a soldier (or officer). There's no ambiguity for what's needed to grow from E1 to E2 or from Lieutenant to Major. There's a literal army of bean-counters who are also double-checking and triple-checking the results to make sure things are going as planned across divisions.
6. Post-military life is also considered: the GI Bill ensures that college-life is guaranteed for soldiers, to be ready to be retrained after their military career. As such, military life can be temporary (4 years or 8 year stints), or permanent (a full 30+ year career). Both lives are encouraged and well supported by the structure. A number of Federal jobs (and state-jobs) even provide explicit bonuses to veterans, to help the soldier transition into post-military life.
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That's how you recruit, and train soldiers in the military. If your point is that the military has an awesome ability to recruit and train personnel, I fully agree with you.
But don't diminish the amount of thought, and resources, that have been poured into the military structure. From pre-recruitment propaganda, to recruitment programs, to continuing education (and the entire promotion structure), the military requires a LOT of money and manpower to support.
If you want to deploy such a "bootcamp" for nurses and doctors, I think I'm in agreement with you. I just want to be clear that such a "Bootcamp" will be extremely expensive, no matter how I look at it. Even if you cut out propaganda, and a bunch of excess spending stuff (military bands and other "morale builders"), the core of the military recruitment / training / post-training structure is very expensive.