I don’t remember anyone saying or writing “eighters” and “sixers” back then.

The last line is the most interesting, "In October 1980, Microsoft's Paul Allen contacted Seattle Computer Products and expressed interest in reselling 86-DOS. The first version of 86-DOS licensed to Microsoft was 0.3. In July 1981, just a month before IBM PC was announced, 86-DOS was sold to Microsoft and renamed to MS-DOS."

IBM reached out to Microsoft sometime in 1980 about an operating system, so SCP would've had at least 8 months to look into why Microsoft wanted their DOS before selling it entirely to them.

Did Microsoft resell 86-DOS to anybody before changing the name to MS-DOS? Did SCP make any effort find out why Microsoft wanted their DOS?