There’s never been a person who went to school for accounting and said:
BUT WAIT, I CAN’T BECOME AN ACCOUNTANT BECAUSE OTHER PEOPLE ARE ALREADY DOINGGGGG THATTTTTTTTTTT.
There are plenty of people out there doing exactly what you want to do—times eleventy thousand. “But there are already so many writers / designers / candlestick makers” is not a valid reason not to do something. In fact, it may be the best reason to get out there and see how you can do it better.
Because you can either worry that you’ll never be able to compete, or, you can make damn sure that the rest of the world needs to worry about you.
Either way, the competition never changes, but your odds certainly do.