The higher you rise up the corporate ladder, the more often you tackle tough issues. High-impact issues are thorny and complex. They require deep focus to unravel their ambiguity. They require time.
But unfortunately, as the value of your strategic insight and expertise grows, so does the number of people who can lay legitimate claim to your time (board members, clients, cross-functional teams, and the growing number of people who report to you). Just as you develop the business acumen and wisdom necessary to understand big problems, you run out of the time necessary to actually solve them.
Studies show that executive "discretionary time" is rarely more than 5-10 hours per week. The rest of your time is pre-programmed — meetings, turning in things requested by others, people walking into your office with a crisis, etc.