I have been publishing with Amazon for almost twelve years, now. I have never had file review take more than about twelve hours. Usually, it doesn’t take longer than six hours.
I am sitting at seven days and counting. I wanted The Schrodinger Paradox: Cataclysm (the first part of the novel) to pop live today, and it hasn’t. I have no idea when–or if–it will. I poked them Friday, and they said to give it until today.
I was busy today–we ran out of a few things without me noticing we were almost out, and I had bloodwork to get done, and the pixie had some dental work to get done. I’ll poke them tomorrow, if it hasn’t gone live by then.
I blame Bezos’s replacements. There’s a lot that went sharply downhill when he stepped back. I really wish it hadn’t, because there’s not a lot of options out there for independents. I really wish he either hadn’t stepped down, or had picked someone for competence rather than for affirmative action checkboxes and ideological purity.
The Godshead Tavern 
I’ll be honest, if I didn’t know a lot of people who feed their reading monkey on a budget by using KDP, I’d probably go wide or go with another publisher.
I am one of those people that use KDP. Andrew uses it even more than I do.
But honestly? I’m not sure I could replace the KDP income if I went wide.