I guess it's more of a thing of marketing than anything else.Actually it is marketing,coz you can't promote each and every instrument that exists on this planet,at least not to the same degree anyway.Some things just stand out,others don't(for the philosophers in here and in all of us,this is cultural colonialism,right?).
But seriously,a guitar is cool.REally cool.To play,to carry around.It looks good hung on wall.And slung over a shoulder.But that thing!Imagine seeing a guy walking downtown with that thing over his shoulders.What would you think?And be honest.That "there goes a musician".Or "there goes ..."OK,I won't finish that,it might look like I'm taking a swipe at Azrael(which I'm not-quick ditto:the guy that insists he isn't drunk is usually the drunkest;)).
Or maybe even our notions of what is cool and what isn't emanate from the marketing we get bombarded with.Go figure.All those "beliefs" we got,they're just classical conditioning(I think that's the term shrinks use).
Either way,long live the guitar.