I'm not sure. I just get the feeling the hotlines are more for people to feel like they're doing something to help, when maybe they're really not doing much at all. I'd like to find out more about what really would help, and hope that I and others would be willing to put the real effort in to make a difference, behind something that works.
The next line immediately after the one you quoted was "Admittedly, it seems that their efficacy to help people in crises (not necessarily suicidal) is far greater than their impact on suicide rates."
Crisis hotlines are definitely doing things, even if the suicide prevention analysis bit is inconclusive.
