Guitar a melody instrument? In classical music, yes--but in folk/traditional/pop music it has ever been a rhythm instrument first--melody comes later, and, in most situations, not at all--

Les Paul   and Django made us start to think about the melodic possibilities, but before them, most guitarists were pretty much chunking away at the chords behind a singer or a soloist. And, for the record, the Gypsies who developed flamenco guitar pretty much did it all, first, and usually better--and, as Flamenco Ted points out, they don't think much of the cheap tricks--