Why it is hard to succeed as senior project manager

Imagine typical large company. Typical carrier path. You are young, perspective, you are excellent at maintaining relationships with your colleagues. You are directly participating in the actual work, changing code, writing tests, integrating. Sure blocked by many bad decisions from your management, but still positive about future, enthusiastic in solving these obstacles. Now, after years, you have gathered a lot of experience, you know what is the right solution for your organization and good message comes: your company has realized that you are the one and you got promoted. Time goes on, year after year: promoted and again and once again...

Suddenly you are in the position of senior project manager, taking all these "suboptimal decisions". Why? What went again wrong?

Conclusion of our small discussion in the team: as you are young and perspective, there is nearly no power in your hands to change something or to make decisions that would lead to bigger improvements. After years and many promotions you got the power, possibilities. But typical project manager either

• forget about issues that he was experiencing many years ago, 
• or situation was radically changed (people, problems, domain, technology),
• or in most cases both

So theoretically there is no chance to succeed.
Fortunately, there are real live examples how some companies deal with this problem. E.g. every employee has directly contribute to the customer value with at least 20%, or every manager has to spend weekly four hours with developers in the same office.
Have you also observed similar pattern in your environment?