Generally the value in recruiters is in passive candidates and not active ones so in those cases it's unlikely that the candidate is working with a significant

Generally the value in recruiters is in passive candidates and not active ones so in those cases it's unlikely that the candidate is working with a significant number of recruiters. Even in the case that a candidate works with multiple recruiters they'll generally all have "preferred clients" who get first look at candidates. And at 15% you're unlikely to be a preferred client for any recruiter except the bottom-feeders who spam every CV to every client. And you don't want any bottom-feeder recruiter to have your CV because many companies have a policy of instantly rejecting any candidate that comes in through multiple recruiters because they don't want to get into a legal dispute over priority. The recruitment market is a fairly complex one (I had a startup in the space so I've been neck deep in understanding how the different players interact). (You're right that if you're recruiting for lots of roles you can get a discount, but it's a tricky path, you really need to exchange information with industry competitors to get a good idea if you're being passed over for good candidates. In some industries like banking this does happen albeit on a semi-informal basis)