Sure you can. That's how most companies operate in the early days. If the company is fortunate enough to grow, it becomes more complex over time. There are more people to coordinate, more products/services to deliver, more external partnerships to manage. There are more problems to solve. There is more competition for resources. This complexity makes it harder for any individual to call the shots. When multiple people start to call the shots, assurances need to be in place to make sure everyone is working from the same playbook. That is the role of the operating system.