Every novel offered to a publisher arrives attached to a short list of books it resembles. Those comparisons do more work in the acquisition decision than the manuscript's own summary.
A publisher is forecasting, not judging
An acquisition is a financial commitment made before anyone knows whether readers want the book. The publisher has to estimate a sales figure to justify an advance.
The only available evidence is how similar books have performed, since past sales are the one real data the trade holds.
Naming comparable titles converts an unpublished manuscript into something with a number attached, and that number is what the acquisition meeting actually debates.
Everything else in the pitch, including the writing itself, is assessed against whether it can plausibly reach that figure.
The comparison also assigns a shelf
Beyond sales, comparisons tell everyone downstream what the book is. The designer learns which visual conventions to work in, the publicist learns which outlets to approach, and the sales team learns which retail buyer to pitch.
A book that cannot be compared to anything creates work at every one of those stages, because each department has to invent an approach from nothing.
Originality is therefore genuinely harder to sell, not because publishers dislike it but because the machinery has no established route for it.
The comparisons have to be chosen carefully
Naming an enormous bestseller sets an expectation the book cannot meet and signals inexperience rather than ambition.
Naming a book that failed commercially attaches its failure to the new title, no matter how well the comparison fits artistically.
The useful comparison is a recent title that sold respectably to the audience this book wants, which is a narrow target and one reason agents spend real time on it.
The mechanism makes publishing conservative
Because forecasts rest on precedent, a genuinely new kind of book has no supporting evidence, and the safest decision is always to decline it.
When something unprecedented does succeed, it immediately becomes a comparison title itself, and a wave of similar acquisitions follows for several years.
Those imitations reach shops long after the original's moment has passed, because the acquisition and production cycle runs slower than the trend that prompted it.
Where the pattern breaks
Independent authors and small presses operate without this constraint, since neither is defending a forecast to a committee.
That is a substantial part of why unusual work often appears there first and reaches larger publishers only after it has generated the sales record the model requires.