no keyboard matches the ease with which Norsk Data's keyboards in the 1980s could type all European and Scandinavian accents 
As far as I remember, they never jumped on the personal computer wagon, and died out as a result, right?
It wasn't quite that simple, but that will do in summary.
Financially, their downfall was the takeover of the British computer company WordPlex, which happened while I was there; this led, in time, to mass resignations, eventually including mine. I could write a whole essay on what was wrong with this takeover, but will restrain myself.
Technically, their 32-bit computers were unusual, because they used their 16-bit computers as a front-end and I/O processor for them. When the PC appeared, they didn't accept it for what it was, but instead spent an inordinate amount of time trying to shoehorn their 32-bit processor onto an ISA board so that the PC could be used as the front-end and look like one of their own machines. This project was called "Butterfly", and was as delicate and insubstantial as its name. When it died, they had no other added value to offer the PC, and had missed lots of other boats. They then, just before I left, hived off the 32-bit processors as a company called Dolphin Server Technologies (which sank without trace, I think), and lived on as a rump, largely in the UK and Pakistan (bizarrely!), providing computer services of various kinds; for instance, for a time they owned one of the UK's oldest bulletin-board systems - Cix.