Reasons I stop reading before getting to your page:
(1) Your query insults as many other published books as fall into "that dreck they're publishing today."
Why I stop reading: trade publishing is not a solo endeavor. You need those "dreck" authors for blurbs, signal boosts, maybe even book store co-appearances. I know that. You apparently do not. I don't want to spend time coaching you on how to not be an asshat.
How you can avoid this: buy a clue at the Clue Emporium
(2) You hope you'll peak my interest with this wonderful novel.
Why I stop reading: If you don't catch pique/peak, I know for an ironclad fact I'll find more mistakes like this in the book and end up copy editing.
How you can avoid this: Make friends with Miss Prunella Picklepuss the Pedant Most Peculiar, or find someone with similar meticulous reading skills who can help you avoid these snafus. Yes, money will most likely be involved.
(3) Your book uses body size an indication of character.
Why I stop reading: I can't sell a book like this, and I don't want to work with someone who writes characters in shorthand stereotypes.
How you can avoid this: Back to the Clue Emporium!
(4) You managed to avoid telling me anything about the story.
If you can't get to the point in three paragraphs, I'm not confident you'll do in three pages either.
Why I stop reading: If I don't know what the story is, why would I read it?
How you can avoid this: Tell me about the story. Start with the name of the main character and what's changed or about to change for them. What's the problem with the change, and what's at stake in how s/he's going to deal with the change (that's a starting point, not a template.)
(5) You don't serve up a problem for your proposed prescriptive non-fiction.
Why I stop reading: if you're not solving a problem, why would anyone buy your book?
How you can avoid this: Understand what prescriptive non-fiction means. If you want to help people, you MUST describe the problem you intend to help them solve. There are no exceptions here.
If you have a book called Thin Thighs In Thirty Days, you have to be clear about the problem created by not-thin thighs.
(6) I can't tell if you're writing fiction or non-fiction
Why I stop reading: Fiction and non-fiction are assessed and acquired quite differently. If I can't tell from the outset, your query isn't effective.
How you can avoid this: Starting your query with a historical event is a clue for NF. Don't start a query for a novel that way.
(7) Word count.
Why I stop reading: it's not worth it if the book is too long or too short. If you want to be a professional writer, you need to know the parameters of the category you're writing in.
For adult trade books, excluding category romance, you really want to be 70K -100K.
For fantasy, or historicals, add another 20K and you're still ok.
These are general guidelines. No one shows up at your house with a smackeroo stick if your word count is 68,087, or if it's 122,343.
In other words, guidelines, not etched in stone but not to be ignored like they don't exist.