Well… it was still far more simple than anything today. Whether we are looking at Concurrent CP/M-86 or at Multitasking MS-DOS 4, these were far more simple than anything OS today. Once we add many users, you start looking at things like Xenix and other early Unices. Those too, we’re more simple than anything today.

Especially as, in Unix, you needed to add things by yourself, so it could be as simple or complex as you needed it to be