No Hconn, in the case of agents (and lawyers, who usually need new clients once they move cases off their desks, and real estate agents, who need new houses to sell once they've sold the ones they have), it's mostly time they devote to keeping their business moving.
If you were running critique service (on the up an up, mind you) then ok. But then the agent would be taking time away from finding clients. Finding clients. That's part of his job.
It still comes down to... if people who write badly want to submit, they will find a way to do so. Money will not be a deterrent to most of these people. But it may be to a person who actually can write, but can't afford a reading fee.
I stick with my orignal solution. Writers, grow up. Yes, we moan about wait times, but it's only because we're emotionally invested on some level (even if we say we're not), and we're only concerned about OUR submission - we forget all the others you have to look at. Some of us ignore the guidelines, making more work for the agent.
Read the freaking guidelines, then go write another book instead of filling the agent's inbox with status requests or hovering over the mailbox like a vulture. Or, what I do sometimes, is start researching other agents, so as soon as that rejection comes in, I have another place to send it out the same day. Makes the rejection sting less, I promise.
It should all rest with the writers. It's hard, but you can do it.