A couple of things add to this understanding of the value (or lack of) a prologue. Many prologues by new writers are incredibly dull and tedious. They operate as an explanation of a story to follow. They are as un-dramatic as listening to someone recite dull facts in a monotone from behind a lectern.
The underlying issue here is that the opening of a story (prologue or chapter one) should draw an audience into a story. A prologue written to explain a story is giving the audience information ahead of drawing in an audience to want to know more. It's a basic mistake in storytelling by struggling authors.
All that said, prologues pop up in popular, traditionally-published fiction, and when they are done well, they are generally accepted.
A mystery by Mary Higgins Clark, Let Me Call You Sweetheart, demonstrates how a short prologue can quickly draw readers into a novel.
First line...
As often as humanly possible he tried to put Suzanne out of his mind.
Some of the questions here, what happened to Suzanne, and how did it involve the narrator? The prime directive of the first sentence of a novel — that the reader must read the second sentence — has been created.
Next line...
Sometimes he achieved peace for a few hours or even managed to sleep through the night.
Whatever happened, it had a major affect on the narrator.
Next line...
It was the only way he could function, go about the daily business of living.
So, not only can the narrator not sleep at night, he can barely function during the day. The question of what happened becomes more powerful.
Next lines and new paragraph...
Did he still love her or only hate her? He could never be sure. She had been so beautiful, with those luminous mocking eyes, that cloud of dark hair, those lips, that could smile so invitingly or pout so easily, like a child being refused a sweet.
Now we know who the narrator can't forget, but who is the narrator? What happened to this woman he loved?
Next lines and new paragraph...
In his mind she was always there, as she had looked in that last moment of her life, taunting him then turning her back on him.
Big question, what did the narrator do when she turned his back? Sounds like he killed her, but we have to keep reading to find out.
Next lines and paragraph...
And now, nearly eleven years later, Kerry McGrath would not let Suzanne rest. Questions and more questions! It could not be tolerated. She had to be stopped.
That this narrator can't sleep eleven years after what happened, and now someone is re-awakening the wound, again pulls a reader forward.
Next lines and paragraph...
Let the dead bury the dead. That's the old saying, he thought, and it's still true. She would be stopped, no matter what.
We end with more questions, who is the narrator? And what does he intend to do with Kerry McGrath.
The first chapter of the novel opens in Kerry's POV. The following chapters are told from different Points of View and bring Kerry into the office of a plastic surgeon who is doing some work on her daughter. Kerry notices something odd about the doctor's young, female patients. They all look, after plastic surgery, like the Suzanne mentioned in the prologue.
Because of the prologue, these chapters create a slow burn of increasing tension that makes the novel a page turner.
When a prologue is written in a way to engage and draw readers into a story, like narration in a well-written screenplay, it will generally be accepted.
Just not always by literary agents looking at new work.
To learn about the craft of storytelling, check out my writing workbook, A Story is a Promise & The Spirit of Storytelling, available on Amazon's Kindle and Barnes and Noble's Nook. It includes a meditation technique that can be used to speak to story characters.