Hi Diki
Most of the people that buy arrangers don’t use 90% of what’s on them, so there is no compelling reason for manufactures to spend money developing extra features. (Open Arrangers probably being the closest you will get)
You can use Cubase on a small screen (Wersi instruments have come as standard with the basic cubase since they were launched in 2000) but as you say the larger the better.
On a separate point I too remember the Atari, and sometimes wish I still had it.
Have a good Christmas

Bill