If all agents did was read submissions, mail the ones they “love” to editors, then wait for the “I’ll buy it!” reply so they can pocket the cash and move on to the next manuscript they love, I’d share your mystification. But they don’t. Every ms an agent agrees to rep commits her to a slew of work for that project and all that author’s future projects: read and respond to every ms the author wants to sell (often multiple times), create pitches and strategize editors, track submissions and nudge editors, make deals and negotiate contracts, and handle rights and other issues for the rest of each book’s life. Dozens of projects in various phases cross an agent’s desk each day. Then there’s the ever-present submission pile and just the business of being in business. An agent’s time is not infinite, and neither is her client list. That agent’s “love” may be just one notch on a stick, with only those mss that hit the “head over heels” mark joining the agency.