Upper management needs to go. Then, install managers who can actually lead people, punish bad behavior and reward good behavior.
The speed at which the job gets done, the customer service provided, and compliance with regulations. Wanting to actually be good at the tasks they perform is necessary to working together well.
Knowing what's going in the building they manage, and taking action accordingly. When an employee is regularly violating policy, and endangering people, punishing them. When people go above and beyond, rewarding them When it's consistent, promoting them when the spots open up.
There is a consistent trend of horrible employees being left in place with no consequences for outrageous violations. Good employees get saddled with extra work and expected to make up the gaps, with no reward for doing so. Not just once, all the time.
Promotion and demotion policies based on merit would be a fantastic place to start. Incentives for going above and beyond would be even better. How hard is it to actually follow the established company practice of having an employee of the month with some basic incentives?