Probably because it doesn't match the ugly gray faky farmhouse decor that they feel obligated to sport. That need to "show off" and compete with real or imaginary cohorts has left them with a dilemma.
<blockquote>MisterEric: This is a single wash arm version, right? No upper...?</blockquote> Correct. KDI-56 is a 16-series. An upper-rack spray arm was introduced on the 18 series..