There are lots of reasons why people would want to stay at a job.
Also, you are going to run into assholes in all walks of life. Learning to deal with them gives you options and puts you in control. If you lack that ability then your only option is to walk away.
Yes some of us are lucky and work remote, have a large portfolio of nice enough clients, and not have to deal with corporate overlords. Let's be real though, this is a very small portion of the workforce.
Not to mention that if you go through the trouble of changing, which is bothersome for many practical reasons, you won't be able to tell if it is better or worse before you've been working for a while, which is a pretty discouraging for risk averse people.
But when one is highly skilled, one does not simply "just quit and get another job".