I believe that environment counts a lot and it sounds like that is what happened to you. I remember a long time ago, hearing about a study done in Math classroo

I believe that environment counts a lot and it sounds like that is what happened to you. I remember a long time ago, hearing about a study done in Math classrooms where the teachers expected the boys to do better than the girls and that is what happened. Simultaneously, they had a Math teacher who expected all of their students (boys and girls) to do well and that is what happened. Part of leadership is believing in the people who work with you. They need to create an environment where everyone can be successful. The people in that environment need to tolerate mistakes. Senior developers need to have an attitude that if other developers mess anything up, it's because of knowledge or skill and that the person is doing their best. Then do what is necessary to help that person overcome their weaknesses. That said, there are people beyond help for various reasons. However, the majority of people I ever worked with want to do a good job. I've been in that situation before too and learned that the best think to do is start a new job search right away.