I guess I don't understand the premise of this thread at all. If you are asking why 'sound art' isn't treated in the same way as the visual arts, the obvious answer is that 'sound art' is a very recent phenomenon, with a few strands streaming out from Russolo et alii but the vast majority of it being an outgrowth of installation art, which is an extraordinarily recent development when measured against the historical timelines of the arts ... there are bazillions of glossy magazines devoted to music and sound, however -- from popular to DJ tech to world to classical to folk to rock guitar to music tech to software to home stereo to high fidelity to noise to punk to contemporary classical etc etc, magazines devoted to sound are everywhere -- but just as there's no "Installation Forum" or "Installation News" or "Installation in America" of course there's not (yet) any glossy "Sound Art Forum" magazine ... and I think that that is just fine. Why on earth would anyone expect this recent (and contested) category of 'sound art' to receive the same coverage or attention anyway as, say, sculpture, which has been an established medium in e.g. europe for 2500 years, at the very least? ... as Ben rightly points out, there is a tradition of art music known as 'classical'/concert hall/'art music'/whatever, which accommodated just as much experimentation as the other arts ... I mean, come on, Cage, Tudor, etc down into today's contemporary classical and electroacoustic musics, there's no shortage of very high profile/visible/well-covered experimentation in classical/concert hall music ... not to mention, 'sound art' barely makes any sense anyway without the institutional/museum/space of presentation/installation impulse tacked on to it ... (Varese's Poeme Electronique was constructed for, and "installed" within, a physical building designed by none other than Xenakis, but we don't call Varese's piece 'sound art', the way that people do today for installation pieces. Why is that? Perhaps because of the institutional/museum/market role in the art world?)
This is all just to say that the attempt to read some sort of cultural lesson or historico-philosophical conclusion about 'sight vs. hearing' on the basis alone of an asymmetric relation between visual art and 'sound art' seems to me to be a very, very sloppy and ill-informed way of proceeding ... and anyway, the question of western thought's privileging of vision over sound, body, and other modes has been addressed by the philosophical tradition since Merleau-Ponty and many others writing in response to Husserlian and Heideggerian versions of phenomenology ... so i would look there ... essay collections in philosophy with titles like the hegemony of vision were all the rage some 10-15 years back, you'd be able to find lots of further ideas/support/new avenues for pursuing your question in them, just my two cents' ...