Internal recruiters are kind of a necessity, though: hiring managers often don't have skills in sourcing candidates, have calendars filled with other responsibilities, and are generally more expensive per hour than recruiters, for the kinds of work that either could do (screening, communicating with candidates about progress, organizing interviews, etc.).

In most cases that I've seen the internal recruiters have strong relationships with the hiring managers and are incentivized to make sure the hires actually succeed.