One can get the proper geometry by just bending the head of the arm (like most tonearms), so that is not the reason for the S-shaped arm. I believe that the S-shape is an attempt to balance the mass of the arm about the axis drawn between the pivot and the stylus. Without the S-shape there is more mass on the "outside" of this axis. Why such static balance along that axis is important is not clear to me (aside from reducing torque in one direction at the pivot). The "cost" of such design is much more mass. For any given mass, other designers would favor increasing the rigidity of the arm instead of trying to achieve such balance.
"S" shaped tonearm ?
what is the reason a company ,such as denon for instance to put an "S" shaped tonearm on there table. ive had both straight and S . and while not high end , i currently have the denon dp500m table . ive heard nor seen an advantage to either, though my experience is very much amature audiophile.