A lot of arranger players, but not many pro (Synth/Workstation) players, pro players have to take into account cost as well as features and the extra cost of adding the arranger features would make them too expensive, (Plus they tend to look down on arrangers) arranger players are primarily home hobby players (This is who the arranger keyboard is targeted at) who don’t mind spending the extra to get extra features, as it’s for their pleasure, not financial gain. (Plus they tend to get intimidated by complex features even though it is just psychological)

Bill