Of course, by that standard, someone with an iPad with a keyboard attached (the ones that are part of a case/cover) could just as easily consider their keyboard "permanent".

Okay but how many people run iPads with keyboard attachments yet don't have a desktop or laptop that would be better for the purpose anyways? I'd wager few.

If that market were larger it would be catered to.

Sounds like a chicken and egg problem. No one does it because the software they need doesn’t exist. The software they need doesn’t exist because no one uses the iPad that way.