I've noticed that on a moderately windy day I can't hear any noise from the hub on my Mercury (just over 6k miles) due to the wind interacting with the helmet or its straps. I've also just changed the very quiet Marathon Almotion tyres to the slightly noiser G-One Speeds but I can still notice the sound difference between 8th and 7th gears. So far there's been no noticeable wear to the numbering on the shifter.
My Birdy Rohloff is a much noisier bike. In addition to the hub having only closed up a few hundred miles I suspect that the chain tensioner and poor chainline will always create some unwanted noise although they have got quieter with use. However, the extra noise in low range is very audible. As it's the number two bike it will take some time to get everything bedded in.