Pros
Up until recently, there haven't been any clear Job Descriptions or Roles and Responsibilities. This really gave people with initiative an opportunity to create the career/job they wanted. As long as you act like you know what you're doing, most people won't know the difference and leave you alone. As long as it appears you are contributing to the bottom-line somehow, you could make a whole career of this.
Kontras
Senior managers are all over-worked. They have too many responsibilities and they become roadblocks for a significant amount of work at lower levels. Every manager is only concerned with "managing up" and employees are left to fend for themselves (this can be a pro if you're a individual with tons of initiative and a little bit of arrogance). Many managers got promoted because they were "next in line" or they were the "favorite". Most have no idea how to manage people and are only concerned with what their boss thinks is important.