I wonder how much of this is also that us folks with more mileage grew up with this sound, and as such have a mental filter to it?  I have worked with or around computers all my adult life, and you really just stop noticing this noise until you are in place where it doesn't exist.  This effect can damp all sorts of noise your brain doesn't care about.  When was the last time you heard your tires rolling down the road? Tuned out the AC unit in the background?