Those iPad apps were never released as computer apps. Not even Surface apps.

This is part of the problem… once you decide to offload important functionality to apps, you really need (if you want to do it right) to develop for Windows, Android, MacOS and iPadOS. That’s way too big an ask for an already underfunded and staffed arranger R&D team! The answer is to have the arranger do it all, problem solved. One OS, one device, no issues with hardware or software longevity, no plethora of dongles and converters to have to set up and break down every night (if you gig). The dev team has only got to code it once (and the code can often be ported wholesale to the next model).

Roland had the answer with the G70. Do it all onboard using the touchscreen and the sliders and buttons. The BK9 was a big step back, no touch screen, and even the sliders didn’t work on the Makeup Tools or Sequencer etc.. Most modern TOTL arrangers nowadays got good touchscreens and sliders etc.. There’s no need for computer or tablet apps.