Thanks M of H: Would a parallel neck make all that much difference to the weight at the head end? And I take your point on musicians and tradition, but tapered necks can't always have been a tradition. Someone somewhere made the first one. A tapered neck would require a lot more skill to make than a parallel one, so it must offer some kind of advantage either in the playability or the tonal qualities of the instrument.

Thanks Richard B: How would that explain mandolins? Mandolin evolution has settled on a size considerably smaller in all respects than guitars, but which still provides sufficient space to pick at the saddle end. A parallel neck would still be narrower at the head end than any guitar neck, and so still small enough to "wrap your sweaty left hand round".

And violins? Leave aside the fact that the strings are arched at the saddle, which if I understand correctly is not for reasons of space but to allow two strings to be bowed at once. Suffice it to say you've got enough space there to play. But the taper on a violin neck, if anything, is even more pronounced than that of a mandolin. Again, a parallel neck would still be narrow enough to play; so why the taper?