When you are a hired professional that is making a comfortable living, it tends to be very hard to move yourself in the direction of becoming a paid writer.
How much do you need to write, publish, network, and amaze with quality in order to get to the position where you will be fractionally closer to the equal amount of money you are making in your current field. The heck, sometimes you want even make the bear minimums of the minimum wage.
Also it depends on what you are writing and how you are selling your work.