I find moving up can aslo be attributed to moving 'around' in IT.
I started of as a SA (Novell 4), moved into the MS arena (Win NT 4), onto Exchange and mail systems, then hardware, then networking (Cisco and Juniper), worked as an instructor, then DBA (Oracle 9i, 10g), then software development and now primarily IT security. I've found that (on average) 2-3 years is enough time to gain a very solid understanding and level of experience to build on, and that these experiences can keep you motivated and challenged. As long as you stay abreast of current developments (and that is the tricky part) you can certainly remain a geek, while not necessarily being actively geeky at work :)
I've been fortunate enough to be in a very large company and move into these positions, excel, and move on. Perhaps one day I'll stop being a techie, but IT Sys Eng. requires (or should) a tremendous depth and breadth of knowledge. I personally enjoy the persuit. I also enjoy being 'the' guy that my division will initial ask if they need someone in a new position.
As a more specific reply. My division's Chief Systems Engineer, though a manager, is most definately still a geek. He just doesn't get to play with implementation details as much anymore.