I am not so certain that it would have made much difference. Microsoft would still have produced both BASIC and Windows, and we may have had the exact same evolution anyway. DigitalResearch's GEM was mired in legal red tape preventing from much evolution.

Also, MSDOS is opensource now.

https://computerhistory.org/blog/microsoft-ms-dos-early-sour...

In all likelihood in that timeline DOS as we know it wouldn't have existed.