I have to disagree a little... I think the Arranger keyboards are more popular than Workstations (especialy in countries besides U.S.), even keyboard manufactures are putting ther latest technology in Arranger keyboards, all the musicians that i know personally, most of them(~95%)use arranger keyboards, and think of a workststion as just something compeletly bizzare or a digital piano or something.
But if you take whole music industry in general, than we can say not "Arranger ignorance" but "keyboard ignorance" .