In the case of Acorn they had hardware memory protection[1] and their own CPU designs[2].

In place of Irving Gould Acorn ended up with some clown called Stan Boland who decided it was better to change the name, stop making workstations and refocus on TV set top boxes. The company was dead six months later.

1. https://www.computinghistory.org.uk/det/29468/Acorn-MEMC-Dat...

2. Not sure whatever happened to the Acorn Risc Machine but I'm sure it'll turn up again. :P