Although I have just sold all of my gear and replaced it by the Ketron SD7 and a dated Korg PA50sd I would like to add my views on this subject. After all I have been playing arranger keyboards for thirty years now..........AT HOME..............
First of all someone pointed out here correctly that it is basically a very very small group of people who go out and entertain the audiences as a one-man band using an arranger keyboard. And this is even more the case in the USA than in Holland, Germany, UK, etc. where you can buy those keyboards on virtually every corner of the street by way of speaking.
Second with the arrival of karaoke and later on very decent backing tapes ( not to be confused with cheap karaoke) many former arranger entertainers who used their arrangers as a band backing up their singing have called it quits. Cause as Abacus here mentioned folks are not impressed by someone pushing a few keys and knobs, but "it helps if their are two keyboards on top of one another " to impress the audiences.
The use of arranger keyboards in bands is in fact superfluous. With the odd exception all of that can also be done and at times even better by using a workstation , notably things like the Montage or Kronos. ( which you will see in professional bands !!)
But perhaps the most important reason why arranger keyboard players are a dying breed is the fact that the audiences want to be entertained and they want to recognise the songs that are on offer. Hence the plethoria of songstyles for Yamaha arrangers and , though less for Korg and Ketrons.....
Songstyles make the player "lazy " and do not invite them to be creative and ARRANGE stuff on their arranger keyboards other than selecting the songstyles, marginally tweaking a few things like volume, reverb ,etc. and creating a suitable righthand sound to go with the style. Mind you that is all that is needed to entertain the crowds, cause they will sing,dance,drink, swear etc. no matter what you play as long as they recognise the song and can sing along.
In a way my health issues over the last 30 years have been a slight blessing in disguise in that I did not have to please an audience and was thus able to take all the time in the world to do what those boards were originally designed for that is to ARRANGE. And having only one or two hundred generic styles on the first generation of arranger keyboards you had to be much more creative and the songs were less predictable....
So we are left with a dying breed of singing arranger performers and ( a slightly larger) group of instrumentalist arranger performers, basically performing to 65+ audiences.
There is nothing wrong with that but it does explain why manufacturers are growing weary of introducing yet another "blow your mind " Top of the Line " arranger keyboard. And it also explains why more and more singers fall back on either the real mcCoy that is a real band or choose to be backed up by the cheapest and most portable solution: decent backing tapes....
All of those will not or not longer frequently consult this forum it would appear.....

regards
John