So far, I have been able to get jobs that fulfill that. My last two jobs have been somewhat important, medical imaging for one (make humans healthier), and greenhouse gas assessments/environmental mapping for the other (make the planet less sick). I sometimes am tempted by bigger salaries, but I do not want to work at a company that produces bad or useless things. Sometimes when I browse the monthly Who Is Hiring threads, I think wow, there's a lot of money being poured into bullshit that ranges from useless to harmful for society.
So, yes. We do exist, those of us mostly happy with our jobs, doing good things. Keep looking and you won't have to sell your soul. :-)