For a community to grow, survive, and thrive, the new people who know a little have to respond I think. Sure someone with more knowledge might come along and offer a better / more complete response, but if the new people don't participate, the community is in trouble. The experienced people will, over time, get tired of answering the same questions over and over again, so its good for the new people to hop in and start answering the simpler / repeat questions.
I certainly don't wait for someone more knowledgeable / experienced to chime in on a thread if I have something I think is worth sharing. If someone else comes along and refutes me, everyone learns.
Why do some questions receive zero replies? As discussed earlier I think, there are innumerable reasons, but I certainly hope that waiting for an 'authority' to chime in first isn't the dominant reason.