[somat]

The question was not dos vs cpm(both of which are superficially the same thing), but dos vs basic, both provided by Microsoft. People get tripped up with basic being a programing language, but imagine dos only instead of the braindead dos command syntax you had a full basic repl as a command line. Note that good dos(with directories, environment variables, and redirection came much later)

Did microsoft not provide disk and program launching functions in basic? Perhaps dos used less memory, memory was a very very tight commodity in 1981.

[wvenable]

To be honest, I don't think BASIC makes a good command line. It's been done but it's not really that great.

As someone who computed in the DOS era, programmed in BASIC, and even installed different command interpreters with more features -- I never once thought that BASIC would have made this better.

The other factor was actually disk and memory size -- you want to keep things as minimal as possible to keep things running fast. When your command line interpreter is reloaded from floppy disk every time you return from a program, you want that to be fast.