Acorn Archimedes Dead
The first ARM-based personal computer — eight times the Atari ST's power on paper. RISC OS ran it; the ARM architecture it debuted now out-ships everything else combined.
The Archimedes (June 1987) debuted the ARM2 — Sophie Wilson and Steve Furber's RISC design, 4 MIPS when the 68020 did 2 — running Arthur/RISC OS, an instant-boot ROM OS.
It was technically dominant (eight times the ST, faster than early 386 PCs) and commercially British — Acorn's education market couldn't fund the architecture's future. ARM Holdings was spun off in 1990; ARM's licensing model then conquered the world.