Wow, a lot being said here.
The big picture:

1-The arranger player today should be using whatever he needs to do a complete job. Karaoke is needed for many of the songs today. Many of the today songs have uninteresting melodies and without the different fills and original rhythm the song falls short.

2-One Man Band VS a karaoke player. No contest. OMB using an arranger keyboard and Midi Files; with the same talent can do a much better job.

3-OMB Vs a live duo or trio, no contest. But that is like comparing apples and oranges. The price and having more than one talent performing makes it a bad comparison.

4-Organs have lost their popularity. Yet they can do everything an arranger keyboard can do and more. When an organ store demos an organ it normally sounds just like an organ. My point; it is the player that killed the organ popularity not the instrument. The same for arranger keyboards.

About ten years ago an update country club called; they wanted a piano player for their dining room. When I told them I played a keyboard they said no. I said, try me for one night. I turned every band sound in my Kn7000 into pianos and soft guitars. I was at the country club for six years. When they hired me for a party I gave them the rest of the keyboard; Disco, Big Band, Latin ----- they were well pleased.
I believe that if the younger players truly understood the potential of the arranger keyboard they would own one.

John C.