I always low-key know that the US is really young, but I always forget exactly how young it is. Like my town is 3-4 times older at least and there are nearby ruins which are in excess of 20 times older

They say “average” volume. What do they mean by that? Or, more precisely, how are they measuring that? RMS? LUFS?

Probably LUFS, but even with LUFS there are ways to make perceived volume louder while remaining within a threshold