The problem the arranger keyboard has with professionals, (And always has had) is that it developed from the easy play features of the home organ, (It’s nothing more than a sophisticated version of that) and easy play doesn’t go down well with pro musicians.
Ironically easy play is also one of the reasons for the demise of the home organ (Or organ in general, although we are getting a bit of a comeback) in that why would anyone pay a lot of money for a 2 manual and pedal organ, then have to learn to play it (including left hand, swell and bass pedals) when you can buy a cheap single manual instrument where you can just push a button and everything is done for you, (Hold a few chords and just play the melody) with no reason to learn left hand, bass pedals & swell.
Things have changed over the years, but you are still limited to what you can play live on an arranger, hence the reason users keep clamouring after new orchestrated styles, as it’s not possible to play your own backing, bass lines etc. on an arranger live. (Unless of course you do like a lot of arranger users are now doing by adding bass pedals and/or a 2nd manual so that they can start playing live again)
Whichever way it goes, the arranger keyboard will survive (Probably in a similar form it is today) just like organs have, (Although organs seem to be on the up with manufactures introducing new models) they will just be at a more subdued level.

Bill