The point being that you've taken a very short term view.
We'll all presumably have careers that last approximately 45 years (whew). All things change over time, and what you find yourself passionate about in high school and college may not be your passion in your twenties and thirties. I pick that age grouping on purpose, because it's typically around age 25-30 that reality starts to set in and it dawns on us that this career we picked...IT, marketing, accounting, ditch digging, whatever...is what we're going to be doing for the rest of our working lives. Yikes! This stuff was fun for a while but we don't know if we see ourselves doing it forever.
There's all kinds of realities that set in. In our youth we want to live life, have fun, forget about responsibility. As life goes on we want families and houses with mortgages. That means our incomes need to increase, and it's not easy to accomplish that without developing political, management, and leadership skills so we can move up the ladder. That gets us further away from the day to day hands on work that got us into the industry to begin with.
Maybe we took on a corporate job and then discovered we had an entrepreneurial itch we wanted to scratch. Maybe we started a business and decided it wasn't so much fun after all to be independent, because the price of that is a lot of responsibility that in a corporate environment is done by someone else.
Then we get on in life. Our thirties, our forties, and beyond. What was fun twenty years ago doesn't interest us anymore. We start thinking about what we want to do with the rest of our lives and it just ain't the same. Maybe we want to write that book, teach at university, travel the world, do non-profit work. Maybe the technology we were so enamored of when we started out has changed so much it's just too much to keep up with, and we just feel like doing "something else".
Then there are what the economists call "exogenous variables", those major shocks outside the mainstream over which we have no control. Maybe there's a whole new worldwide economic order, like jobs moving overseas or the rise of the Chinese economy. Not so easy to work in our chosen field anymore, and we find ourselves having to evolve just to survive.
I say all this from the perspective of being in my fifties, and having gone through all the passions and disillusionments. I have children in their twenties who are full of piss and vinegar, just starting out in their own chosen careers and convinced that this is what they'll be doing for the rest of their lives...because they love it so much. I can tell you in all honesty that of all the hundreds, thousands of people I've met throughout my life, there isn't one single one of them without exception that's still doing the same thing in their forties that they were doing in their twenties.
So yes, be creative. But be flexible too. And don't worry if things change, even if you're not the agent of that change. Evolve or die.