The title is misleading a bit. The predictor power of an interview changes as a company gets better at doing interviews.
What do I mean by getting better? (1) Asking the same questions (2) Having a BARS scale for scoring, which means you define the characteristics of a good response versus bad response before interviewing anyone (3) Interviewers received training to do this job impartially (4) Everyone on the interview panel agrees they don't make decisions just based on gut feeling! or saying I have a good feeling about this person!
To summarize, Interview is okay if it's done correctly - It's not great though but not doing interviews have its problems/biases too :)