There’s a lot of people just like me here on CakesDecor that turned their hobby into a legitimate “pay-the-bills” business, so it is certainly doable. Notice I didn’t say easy. And I suppose based individual circumstances, it may not truly be an option for EVERY one.
I highly recommend “The Practical Dreamer’s Handbook”, which is a guidebook on turning your dreams into a reality. I would also suggesting asking yourself why caking won’t pay the bills. Write down the reasons it won’t and then think of 10 ways to overcome each of reasons.