Okay, here's what I'd like to know. About what percentage of the slush pile is made up of stuff that's this outrageous? IOW, if I act like a professional and write well, what portion of the slush pile am I really competing with? If you get a lot of clueless subs like this, that it's needless to say have no chance, why do so many excellent writers, published and unpublished, have to submit like ten times and then sell the ms., unchanged, on the eleventh? That ms. must have impressed some or most of the first ten as being of publishable caliber. When you find these writers among the unspeakably bad slush, aren't you saying "OMG, this one is actually for real"? Yet it's almost sure to get just as rejected as rhyming vitamins.
Remember earlier when I said that a good 50% of the kitchen-full-o'-slush was so inappropriate, illiterate, or crazy that it makes you despair for the future of literature? You didn't really believe me, I see.
That's ok. It's a tough concept to get your head around until you see the stuff yourself. Watch this space for some examples.
And then let's remember that once you've excused yourself from the "what are you using for brains" category, you still have to navigate the difficult terrain of writing a really good manuscript. A very sizable chunk of the other 50% are just not ready yet. They have plot problems, or haven't figured out who their audience is. They have good voice but no story. They've got part of what would make a really appealing book, but it needs something more. Etc.
Ok, so let's assume that you've put yourself in the "wow, this could be published" category. You still have to find the publisher at which you could be published. Maybe one publisher has declared a short-term and undisclosed-to-the-public moratorium on acquiring picture books. Maybe another publisher has something already on their list that's too similar to your project. At three other publishers your manuscript is read by someone other than the editor who would see what your manuscript could be. And at four other publishers it might be seen through a haze of bad-slush-induced grumpiness or haste. These can all be factors.
This is, again, why you must keep working on your writing, and keep submitting. In an ideal world, there would only be the publishable stuff in the slush pile, and every editor would read every submission, with fresh eyes and a hopeful attitude. Instead, we get 15,000 manuscripts to slog through, knowing as we do that many thousand of them are dreck. But we keep trying, and so should you.