IME and IMHO that's not reality. People do care about the truth, as well as power, and many other things. They generally are truthful. It's also (enlightened) self interest and we are highly evolved social beings, able to organize on the scale of billions.
The idea that we are only or mostly our worst, most self-destructive instincts and not, for a equally likely example, only our best instincts, is an odd one, but people love to think it these days.
Caring about power yields more power. All people are a mix of all these qualities, but if some qualities help to survive/succeed in an organization, the organization will be lobsided towards these. It doesn't take evil masterminds, just bits of "worse" instincts that get amplified in the dynamics of the organization.
I find it quite apparent in academia too. Academics do care about the truth and such, but to survive in academia you have to "play the game" even when it means being a bit flexible with the truth or other such principles. Or conversely, being too rigorous with principles means you don't usually stay a (paid) academic for long.
The idea that we are only or mostly our worst, most self-destructive instincts and not, for a equally likely example, only our best instincts, is an odd one, but people love to think it these days.