I think it is more to do with the apparent fact that ALL Yamaha arranger keyboards are home keyboards only. And SERIOUSLY geared after the Yamaha home organist and organ users.
That is not a criticism, just an observation. They can do it, are doing it and are being successful at it... (IF you measure success by $'s and C - for me success is not money related at all)
Just because a small group disagree or even become quite vitriolic in complaint, will make scant difference, or even raise an eyebrow at the Yamaha decision making executive level!!!
This is the market (home user semi/fully retired) with the most cash to be gouged, so Yamaha are unashamedly milking this segment for every cent it can get.
"Greed is good" (Gecko-Wall Street) ....for some, not others. But Yamaha as a corporation, certainly follow this principle, as well as ALL other corporations follow it....well maybe one day, and perhaps that day is coming sooner than they think.....they will start to reap what they have sown!!