Robert Heinlein said much the same thing about submitting-until-sold.

Since I'm not a writer (or publisher) myself, I don't have any first-hand experience to turn into advice, but I've heard an editor (don't remember who, alas) quoted as saying "Submit it. Don't reject it for me; that's my job." This sounds like a good thing for raxvulpine to keep in mind when submitting the novella....