The "good ones" will put in a lot of work on your behalf. In return, they don't want to represent something that won't sell (and make them the $$ which is their reward), so many (don't know about all, y'know) will only represent a novelist, e.g., who has published one and has another nearly done and something to show toward a third cool idea .... what Mad called the Catch-22.

It's not necessarily a bad thing, but it's best to be aware of what the realities are, imo.

HJ