To be honest Gary did lack some of the harder edge business side that Bill had, but clearly Gary was actually better at producing operating systems. I recall DR-DOS being my preference back in the late 1980's for its better extended memory management. But if Gary had been at home and got the deal with IBM, he may well have ended up having Bill work with him. It's likely though that Bill would still have pulled ahead based on his "business acumen" much as he did with Paul Allen.
Watch at https://youtu.be/sDIK-C6dGks