A crack in the funnel pulls away all of the people who have a complete book but don't or can't edit it. The people who make it through the funnel are ready to query literary agents and publishers. ... Only to find out that there's a sieve.

The sieve represents all of the authors who query literary agents and publishers open to submissions. It's a random chance of when you'll pass through the sieve, and even the people who query a "perfect" book aren't guaranteed to pass through into publication.