I think humans are mostly visual and that. on average, our eyesight is stronger than our hearing. </speculation>
I think you'll find that's the other way around; our eye sight is pretty poor and limited - good for tracking animals to hunt and to jump between trees, pretty poor otherwise. (Fun fact; when your eyes move your brain stops processing visual data until it stabilises again - so when you look left or right as a car driver all you saw was what was in front of you when you started and where you were looking at the end, your brain made the rest up.)
In fact you'll notice audio drops/glitches much easier than you'll notice visual ones simply because your brain isn't doing as much compensation.
(As for a dog; dog's worlds are very smell directed rather than visual based thus the rabbit problem.)
Graphics are one of those things which are just easier to show off; you get screen shots and wonderful flashy trailers which look good on a 1080p screen and give you lots of Hollywood wiz-bang; where as audio setup for most people tends to suck - $10 speakers attached to an onboard sound system with the same fidelity as an ant blowing into a trumpet.
That said, audio tends to get a fair amount of processing time dedicated to it; in OFP:Red River for every graphics frame we were rendering on the console (30fps) you would see at least 5 audio frames of processing happening and eating pretty much a whole core on the X360 so audio can get a pretty good chunk of resources. (The audio guys also put a lot of work into the sound design, the J-DAM explosion sound was a thing of beauty and worked well with the particle system around it.)
As others have said, the audio design in many games is good, you just don't get it thrown in your face because it tends to be more subtle.
My favourite bit which springs to mind is the background computer chatter in Dead Space; sets the tone really well and when you focus in on it then it is damn creepy... Vampire : Bloodlines also had some pretty cool sound design, in fact I hold up the first mission proper in a haunted hotel as one of the best bits of game design I've encountered as the graphics, sound design and pacing are just spot on.