I'm mostly motivated to write non-fiction by wanting to share information about a topic in which I'm passionately interested. When I write a short story, it's not so much inspiration as it is imagination urging me to commit a story to my computer screen and/or paper. Both of these writing outlets give me satisfaction.
This is not to suggest I'm not also motivated by money. I'm currently editing a manuscript for a fiction book writer and hope to gain many more of these assignments, lucrative ones. Like most writers, I want someone to "show me the money."
It's probably too late in my life for me to write something original and good enough to bring me fame, which is what I'd have wished for several decades ago--in addition to the satisfaction and money.