Are you in or have you been? You sound like you don't know what you're talking about.
The vast majority of people I've met through my six year Army career (Intel, so a bit jaded) fit none of those molds. The military is literally just a job, I don't understand why so many people think that people in the Army all joined out of some sort of desperation. I get that there is a certain sort of elitism and "I want to be different from Grandma so instead of worshipping the troops I'm just going to look down on them" but it's really dumb. A lot of people use it for free experience as a launching point into one career or another, especially into the intelligence or cyber worlds. Some people just want to travel, the military is awesome for that.
Personally, I joined because I wanted to. I'd always been fascinated by the military and didn't want to make a poor decision on a college major, waste money, and get stuck only being qualified for jobs I hate, so I went to a recruiter to see what my options were. I ended up having the Army pay me a salary to learn Arabic at a college level for two and a half years, then got springboarded into working directly for a three letter government agency for three years as a green-suiter. I was able to buy a house at the age of 20, I've got a B.A. in Arabic studies that cost me literally nothing, and I could get a pretty hefty salary as a contract-linguist for said agency if I really wanted to. (I don't, I'm currently looking into starting my own business because I don't actually like translating that much.)
Without the military, I'd probably be an unemployed 23 year old indebted college grad sitting in my hometown, browsing reddit, smoking pot and wondering why the fuck no one is hiring History majors with no work experience outside of fast food and retail. All of my buddies that got out within the last few years are working high paying jobs at one agency or another and loving the hell out of their lives.
That's intel, but there's also the Signal Corps, Engineer Corps, Mechanics, etc. all those are frequently used as launching pads into high paying careers in IT, Engineering, Diesel Mechanics, etc. You know how every job you ever apply for requires experience on top of a degree? Well 4 years as a ___ in the military often looks pretty sweet on a resume. Most jobs outside of combat arms have tons of transferability.
But even combat arms has its perks. Some people simply think riding around in a tank and blowing shit up is cool. Some people like hiking and backpacking, so the ability to get paid to do that while also getting to shoot "bad guys" in the face has a certain allure to it. Those people generally make the Army a career, but whatever. 20 years for a sweet as pension and the ability to "retire" at 38 and still have time to start another career while receiving a pension doesn't sound terrible to most people.
The whole idea that the military is just a big grind house taking poor kids, making them kill brown people, then leaving them to suffer as homeless vets with PTSD is simply not true. Sure, some people end up homeless, very few, but you'd also be amazed how many non-vet homeless people are just pretending to be vets for extra sympathy because no one knows that they are getting bullshitted. I don't think I've ever met a REAL homeless vet, and I'm generally the type of dude that'll give a homeless guy a cigarette, smoke up, and chat with him/her for a little while. They're usually full of shit. It's a mental health thing, you know?
I just want to try and dispel this myth that we're all desperate and end up in the Army because of it. Don't let Grandmas influence your opinions too much. We get annoyed by their blind worship, too.