tl;dr: Living is expensive, and writing doesn't make much money, and writers don't often acknowledge that they rely on external funding:
I attended a packed reading (I’m talking 300+ people) about a year and a half ago. The author was very well-known, a magnificent nonfictionist who has, deservedly, won several big awards. He also happens to be the heir to a mammoth fortune. Mega-millions. In other words he’s a man who has never had to work one job, much less two. He has several children; I know, because they were at the reading with him, all lined up. I heard someone say they were all traveling with him, plus two nannies, on his worldwide tour.
None of this takes away from his brilliance. Yet, when an audience member — young, wide-eyed, clearly not clued in — rose to ask him how he’d managed to spend 10 years writing his current masterpiece — What had he done to sustain himself and his family during that time? — he told her in a serious tone that it had been tough but he’d written a number of magazine articles to get by. I heard a titter pass through the half of the audience that knew the truth. But the author, impassive, moved on and left this woman thinking he’d supported his Manhattan life for a decade with a handful of pieces in the Nation and Salon.