crossword, if you're thinking that going directly to publishers is a shortcut, or that it will in some way net you more money since you're cutting out the agent step, you need to reassess your understanding of the situation.

Slush submissions - the giant pool you'd be putting your work into - are the last ones to be read and considered. That's after referrals, new works by authors already with the imprint, and targeted-agent submissions. You can spend literal years in a slush pile for a big house, slush-submissions are often on an exclusive basis (meaning you can't sub that piece of work anywhere else, which is a restriction not put on agented submissions, and if they read it and reject it, you might never know because they might not tell you. Many places are "no reply means no," only you don't know how long it takes to get an answer in the first place, so you keep waiting.

And as for the idea that you can "cut out the middle man" or something, any slush submission is going to get a boiler plate offer. It's a standard low-ball offer, and since you're on your own, you have no leverage or experience with which to negotiate for a better deal.

For example, lets say you're offered a boiler plate $10,000 for one book:

Sure, $10,000 sounds great, but you're looking at that $10,000 as a whole. In reality, it would be chopped into halves or thirds, payable over a few years, and you'd still have to pay taxes on it.

Those caveats still apply to agented deals, but that $10,000 grand can end up being $50,000 in a good agent's hands. Sure, they get their 15%, but 85% of $50,000 is a whole lot more than all of $10,000.

And if they can negotiate for a series, rather than a one-off, it's even better.