From Simon Schama's Why I Write:
Orwell’s four motives for writing still seem to me the most honest account of why long-form non-fiction writers do what they do, with “sheer egoism” at the top; next, “aesthetic enthusiasm” – the pleasure principle or sheer relish of sonority (“pleasure in the impact of one sound on another”); third, the “historical impulse” (the “desire to see things as they are”), and, finally, “political purpose”: the urge to persuade, a communiqué from our convictions.
To that list I would add that writing has always seemed to me a fight against loss, an instinct for replay; a resistance to the attrition of memory. To translate lived experience into a pattern of words that preserves its vitality without fixing it in literary embalming fluid; that for me has been the main thing.
No mention of the income at all?