O Snarkish One,
Would you kindly opine further about what might be going wrong--in the market, in the stars, wherever--when a fine agent with many successes throws himself behind a novel and works long and hard on its behalf (may his tribe increase) but simply...cannot...place it?
If life was fair, there would only be blue skies with puffy clouds and nary a hint of rain.
If publishing was a fairway, there'd be duffers on Broadway and shouts of "Fore!"
If publishing was a fairway, it would sell vegies, and Malomars too (inside NYC joke).
If life was fare, you'd be a bus.
But life isn't fair, good projects get overlooked and it's enough to make good agents scream with frustration. We all have at least one good book we can't sell.
Bottom line: it sux. Suck it up. Write another one. (easier said than done, I know)