The military needs people who want to fly airplanes and "punch out" and people want to go all the way and make a career out of it. Not everyone is going to be a lifer. Not everyone is going to want to live with 20 years of **** sandwiches and having to check all the boxes to pin on O-6+. People have choices.
I don't fault anyone for wanting to serve their minimum commitment and decide to move on to "bigger and better" things after the military paid for a bunch of their training as long as they give it 110% while they're beside me.
As others have said, being in the military involves a lot more than just flying. I know aircrew who got tasked to man homeless shelters for 1-2 weeks on end during "Super-Storm Sandy" a few years ago cleaning up ****, ****, puke... you name it. "For State and Country". There will definitely be some things you end up doing in the military that you never thought you'd be doing when you swore in, but that's the job.