It’s all down to marketing

Arrangers are designed for Home Players, and are marketed to them. (If you asked a home user what a workstation was, most wouldn’t have a clue, in fact as manufactures put the workstation name on their arrangers, most home users think they are)

WS are designed for Pro Gigging/Studio musicians, and are marketed to them, and this is why most of them don’t have a clue what an arranger is. (Most consider them as toys for young kids in their bedroom)

If you want to change the above, you will have to change the manufactures mind, so as to market them at the other set of users.

WS & Arrangers do cross each other’s lines at times, but in very very small numbers.

BTW: The reason Korg arrangers have more advanced features, is because they do not have a long term home user market history, so they have worked from the WS down, whereas Yamaha has both, and so their arrangers develop bottom up.

Bill