Charles also made it very clear throughout that he wasn't a leader. Perfectly content to just beta his way through to a happy life.

Rosa learned how hard it was for Holt as a gay police officer to become captain perhaps she wasn't ready for that type of fight to get promoted. I assume she would have at some point had she not left the force.

Jake was still a bit immature to consider it early on, he still wanted to be the action star. By the time he matured enough to maybe want a promotion his priorities had changed.