Well, some people don't build model airplanes after work. They raise families, work at food banks, take care of their elderly parents, sponsor people in AA, and so on. Ideally, every waking minute of your life will make the world a better place, but it's a luxury to expect a career that really means something.
Good luck on your career decision. It sounds like you've already made up your mind, but in general it's a good idea to talk to your boss about the soulcrushingness of work well before you want to quit. It's possible that she would be willing to give you more variety, responsibility, or freedom to keep you around.