A bad manager will surely lead to the end of that company. As a manager, it is your duty to oversee all your employees and ensure that they carry out their respective duties. It is okay for you to replace an employee when you feel they are not doing their job properly, not necessarily firing the person but moving them to another department where you feel they will perform better. Also in a case where the manager has a bad attitude and can be overbearing, the employees will certainly seek for job elsewhere and when they get it, they will leave. If a company falls, nobody cares about the employees, it is the manager they will hold responsible.