When you write a book, you are asking someone to make an investment in their time and money. A column can come and go as the weeks pass, but a book needs to be timeless.
A writer writes. If you want to be a writer, write.
If you want to lose 40 pounds, you order salad instead of fries. If you want to be a better friend, you take the phone call instead of screening it. If you want to write a novel, you sit down and write a single paragraph. It's scary to make major changes, but we usually have enough courage to take the next right step.