I’m an editor, book doctor and writing coach who works with a very diverse group of writers, from folks who self publish to folks who have large publishers bidding against each other to publish their work.
The numbers here align with what I’ve learned.
It’s all about what publishers think will sell.
An unknown writer rarely get a big advance for a first book.
That being said, one of my writers got a six figure advance for his first novel, as part of a two book deal.
When he submitted it to the agent who ended up representing him, she said it was the book she’d been waiting for for years.
So that happens too.