I’m a journalist and I’ve been a consultant to those looking for a traditional book deal. Historically, the big publishers looked strictly at the book content.
The internet changed that. If you have 500,000 followers (generally agreed upon number) they will publish things they may not have in the past. I got a client of mine 2 book deals with two major publishers. He went with the bigger one. I knew I had a likelihood of getting him a contract. Why? He was an expert in his field (and a lawyer) and his business book concept was fresh and new. So he was an expert with a fresh take on an old topic snd it was a niche field. If you want to increase your chances with big publishers you need to read the competition in that genre. Then I would suggest you go to the bookstore and sit in that section and write down all of the publishers that are in your niche. Many of these traditional publishers have specific imprints and pitching your submission to that particular imprint of say Penguin is better that pitching it to an editor of the main publishing house.
Also, as a journalist I get pitched by a lot of people who call themselves authors. The first thing I do is go to Amazon look up the book and see if it was self published. Self-publishing is known in the industry as subsidy publishing. The slang for it is called Vanity Publishing because you don’t have to be a great writer you just have to have the money to publish it. I’m against self-publishing because it tricks unknowing writers into believing they are achieving Inc their dream only to take thousands or tens of thousands from them. Self-published books are difficult to get reviews or PR/Press for and most bookstores won’t carry them. But self-publishers won’t tell you this. This has been the truth about self-publishing for decades. I wouldn’t give up on traditional publishers if I were you. I would just discover some of the other truths about publishing that increases your odds.
I started out in marketing and PR consulting before I got published years ago and became a freelance journalist and former business columnist who now writes about relationships. That business background has helped me over the years because I it gives me a unique perspective. I’m the shoemakers daughter because I’ve spent a lot of time making other people’s dreams come true and have only very recently decided to concentrate on my own growth professionally and digitally. But there are absolute ways to increase your odds with traditional major publishers.