My feeling is there are more accordion players in Europe than the USA. Many Accordion players find it easy to play an arranger keyboard. Most arranger customers in the USA that I had when I was in retail, all started with the accordion as a kid. I am talking about an age group of 60 to 80 years old. So this age group was playing accordion in the 50's or 60's.
In Europe the accordion is a much more acceptable instrument. Ketron in particular has made products to be used by accordion players since the company began.
Theyeven made a arranger with accordion buttons.
Since europe has more accordion players, they in turn have more arranger players.
Just my opinion.
When I started selling arranger keyboards back in 1986, in was piano stores that carried the product, not music stores. Music stores had the dx7 & korg m1.
Piano stores sold the 1 finger play, to home organ customers who had lowery or kimball or baldwin organs with easy play features.
The divide started with piano stores carrying psr-60,70,80 & 90's and selling them for $600 to $900 bucks. Where as music stores had the dx - juno and korg synths/workstations.
Many organ players where accordion players.
Get where I am going ?