My comparisons were with the operating systems available in the universe of operating systems, and available for study by designers of other operating systems at the time Windows 1.0 was being designed. The source codes of operating systems were generally freely released by the manufacturers in 1983. I know, I studied the microfiches myself. Imagine that, with all the BS talk nowadays of ‘open systems’ and other semi-meaningful buzzwords, as if everything was invented after the users of these buzzwords were born.
But you can win the argument since you really want to.