[Discussion] Are there too many agents relative to editors?

I was listening to a publishing podcast and they mentioned there are a huge (and growing) number of agents compared to editors, and how it's making it harder for books to make it through submission--too many sellers, not enough buyers. Is this true? Are there "too many" agents, and not enough editors to buy books? Following on that, what percentage of agented books really do survive submission and make it to a book deal? I have heard all kinds of numbers on that.