I would argue that the job markets are incredibly sticky. With HFT, dollars are fungible and shares usually don't have a regional preference for their buyers. There also isn't a resource cost of acquiring, training, and integrating a new share into your portfolio.
Recruiters typically work for for-profit businesses, that maximize returns on sales, meaning they are going to try to charge organizations slightly less than it would cost the organization to do it in house.
The increased liquidity in job markets drops the amount of time it takes to match a job opening with a job seeker, which eliminates inefficiencies. You're not factoring in the income difference someone makes by being placed in the ideal job sooner.
> the income difference someone makes by being placed in the ideal job sooner.
I don't know how you can tell what I'm factoring in or not, since I deliberately avoided this calculation. It can benefit either employees or employers, depending on elasticity / market power. In other words: you're not factoring how much faster expensive senior employees can be replaced with recent grads ;).
That said, there is also a cost to sloppy, spammy recruiting, illustrated in the other responses: it can end up increasing stickiness if enough people start ignoring all recruiting communication because it is all spam. That makes it even harder/more expensive to recruit, and grows the market for recruiters. There are some nasty incentive structures in there.
Recruiters typically work for for-profit businesses, that maximize returns on sales, meaning they are going to try to charge organizations slightly less than it would cost the organization to do it in house.
The increased liquidity in job markets drops the amount of time it takes to match a job opening with a job seeker, which eliminates inefficiencies. You're not factoring in the income difference someone makes by being placed in the ideal job sooner.