When the BBC Micro was dominant, the company realised that it had enough money to develop either a next-generation school micro or its ARM processors. It chose the latter and, financially, that decision cannot be faulted. The Archimedes/RISC PC was always going to be a kooky and expensive niche, supported only by a shrinking band of Acorn fans, but its processor is fast taking over the world.
Like me. I went through three or four RISC OS machines and still have a working RISC PC. Had to move to Wintel for a few years until Linux desktops became productive enough.
Attempts to reach the present announcement have been going on for a long time. RISC OS Open Ltd, aka ROOL, were formed several years ago, with exactly this as their ambition. Looks like the eternal bitchfights between IP owners have at last been settled.
H'mm. Maybe my next upgrade will be a Pi dual-booting RISC OS and Devuan. That would be nice.
And I'll tell you what else. How about a nigh-on unhackable ROM-based, compact and lightning-fast but still fully-featured, and Open Source, OS to power the IoT? That would be nice, too.