I would definately agree that people's needs & lives change, resulting in changes in careers all of the time.
I started college as a music major. Until that time, that's all I could have imagined doing. After 2 years of music school, though, I'd had enough. So 2 1/2 years into my schooling, I changed majors to "Speech & Communications". I intentially kept a broad major of communications not because I wasn't sure what I wanted to do, but because there's so
much I want to do! And that degree gave me a good general background for a lot of things (from technical aspects of TV and radio productions to management). I am planning on pursuing either an MBA or an MA in the near future (but also want to save up some money for that first since I have racked up enough in student loans already).
At the moment I'm in project management at a copy shop, and vying for a position as an assistant branch operations manager for that same company. My current job is loosely tied to my major, but I hope to eventually pursue something a little more creative and "artsy", one of my goals being to teach communications (especially film studies) at the undergraduate level.
Something funny... one of my friends from school has her BA in Art and Art Therapy. She teaches art part time at a private elementary school, but also works for the same company as me in several capacities. Her focus and best subjects as a student were printmaking and photography: replication and duplication, as she says. And now she's making copies.
(Her joke, but pretty funny).