Recognize that liveatc doesn't catch everything. That one recording switches from departure/arrival throughout. When it's on the arrival frequency, you aren't hearing what's is going on departure etc.

BPF nailed it pretty head on. I agree that the system is set up and works that way, I don't think there is much of a secret about that. I can't believe how much complaining there is about the fees for the GA pilot. Really? Chances are your plane burns about that much in fuel costs in an hour or two....