It all comes down to choices....an arranger keyboard plays the way you choose to play it..

My G70 can be played as a piano (better than most), with a decent feel and sound...and it can be played as a full piano mode arranger , if you choose..

It can be played as a decent organ (real drawbars)..again , better than most..

There is an example of two dedicated instruments that Pros and Purist prefer to play.....and wouldn't you know an arranger can fulfil the job.

And it is a perfect drum machine..(yes pros and purist use drum machines)..

We have choices..electronics is not the hinderance..we are..

I would say ..those that complain..may not be the capable players they think they are...turn off the auto stuff..and find out what you are made of..

I use top arrangers because they are capable to meet my needs...it could be left hand bass and a rhodes..along with a drum machine....also the mic and effects at my finger tips..
Try setting up the "real" instruments and workstations to duplicate this...and you can understand why arranger keyboards are not dying off..only savy players are dying off..