We've touched on this topic before. If you see a management opportunity looming in your future, get comfortable with giving up some or all of your technical edge, and be sure you'll continue to be worth your salary before you make the move. The price of new hires continues to rise. It's a variation on the law of supply and demand that affects managers' salaries. Frequently bringing in ever more highly paid trainees creates turbulence and inequities in the entire group's salary structure.
Seniority still counts in many companies.
The same compound interest that makes your savings account balance rise has the same effect on salaries over the years. Rightly or wrongly, some employees' salaries become higher than their managers' simply due to tenure. Relocating an employee from a region of the country with a high cost of living to a region with a low cost of living can result in salary inequities. A classic case of workers earning more than their manager occurs in the commission sales world. As we said, these situations aren't uncommon and shouldn't come as a surprise or cause undue anxiety for the manager.