The Non-Fiction Advantage (and Disadvantage)
Thoughts on timing and sales for the two different genres.

Last night I attended a PEN America event. Over the course of two hours, I met several first-time authors whose books were dropping over the coming months. One penned an interesting novel. Another wrote a collection of poetry based on her life experiences.
Part of me was a smidge jealous. After all, their works were timeless. If their publishers released them into the wild next week or next year, not that much would change. With rare exceptions, there's no ticking clock on a piece of fiction.
The Other Half
Non-fiction writers, of course, face a starkly different environment. If you're writing about tech or cryptocurrency criminals, speed kills. Every day may well result in fewer sales. It's that simple. Wait too long on a subject, and you and your publisher may be delivering a book that's DOA.