This drives me nuts because there are a large number of grad students (myself included) in our small department are working on a certain field of which the professors know nothing about. I don't think the faculty are oblivious to this, but I'm not sure why they continue to not hire in this area. Perhaps it is because this is a harder area to publish in. One professor in our department told the grad students that "we look for people who can publish." Another professor recently said that "faculty preferences" would determine our next hire (a faculty member is leaving after this semester), and all the grad students rolled their eyes because the "faculty preferences" ignore what the grad students need. I spoke with a recent grad (landed TT at an R1) that was appalled that this same situation (hiring where we don't need hires) happened last year too.
Q: Is it normal to hire/interview candidates that look like current faculty? Why won't they branch out? Can the grad students do anything, or should we return to our corners?
PS: I'm not sure why the department continues to admit students that study this area, but this continues to happen. I came to this school because it was one of the few I was admitted to... I did, however, make the decision to reapply to new schools this past fall, and I hope to hear some good news about changing universities in the coming months.