The article refers to Amiga, which came out in 1985 with a multi tasking OS (Workbench). That was a popular computer, at least in Europe. It was not as popular as IBM PCs, but it did show that it was possible at a reasonable price.
Although the Amiga Workbench has pre-emptive multi-tasking it not only has but encourages use of a backdoor to switch off the pre-emption. As a result you don't gain as much as you might hope over systems with co-operative multi-tasking like Windows 3.x - Apps A, B and C may be getting along just fine, but if App D is selfish enough they're all screwed anyway. Together with lack of memory protection (for hardware cost reasons initially) this means Amigans don't end up making as much use of the multi tasking as you'd think - if I run A, B, C and D but then the system crashes, who do I blame?
That backdoor is still there and causing problems in 2022. You can buy a 64-bit multi-core "modern" Amiga but it is still running an OS with a stop-the-world backdoor to switch off pre-emption, and so it only ends up using a single core in 32-bit mode. Or you could put Linux on it.
It's not acceptable for 2022, it was bloody amazing in 1985. Obviously you pick the apps you run, so if you stuck to well behaving apps (and there were plenty) the multitasking was great. Crashes were a fact of life to be sure - one was wise to save often.
