It's not akin to that at all. External recruiters are typically paid for placement (i.e. they get a commission paid on a hired employee after they're hired, typically 20–30% of base salary). There are good ones, but a non-trivial portion are just cold-email spamming everyone whose LinkedIn profile looks even remotely like it might match the jobs they're recruiting for and forwarding on anyone who replies.
For a company/hiring manager, one great candidate a month is far more valuable than a few dozen ones who aren't even close to matching the role. They're not saying "do the work for us", they're saying "if you want us to take your sourcing seriously, send us quality, not quantity."
For a company/hiring manager, one great candidate a month is far more valuable than a few dozen ones who aren't even close to matching the role. They're not saying "do the work for us", they're saying "if you want us to take your sourcing seriously, send us quality, not quantity."