the QL (a 680xx home computer launched two weeks before the Mac)
This implies that the QL was a competitor to the Mac. My sincere apologies if that wasn't your intention, but anyone who has used a QL and a Mac would have a hearty chuckle at the thought.
Sinclair guessed and gambled on the next big thing in small business micros being multitasking. It wasn't. That came more than a decade later. The next big thing, we know now, was the GUI.
Also, the QL was far too savagely cost-cut, as was Sinclair's wont.
But what is rarely considered is that the QL inspired more derivative designs than almost any other micro except the IBM PC... if you exclude the dozens of illegal Sinclair Spectrum clones in the Soviet Bloc.
The Thor, Thor II, Thor III. The Aurora. The QXL card. The Q40 and Q60, and later, and still around now, the Q68.
The OS was rewritten as SMSQ/E and was sold in a form that ran on Atari ST hardware, too.
And the many that didn't run QDOS: the Merlin Tonto, ICL OnePerDesk, Telecom Australia Computerphone.
About a dozen different computers from half a dozen companies, all QL compatible to some degree, developed and sold over some 35 years, is pretty impressive, IMHO, for a machine widely seen as a flop and a failure.
This implies that the QL was a competitor to the Mac. My sincere apologies if that wasn't your intention, but anyone who has used a QL and a Mac would have a hearty chuckle at the thought.