I was referring more to potential, as opposed to what he actually did in software development. Per stories from Harvard, he had some mathematical talent. With talent like that he could have essentially pursued whatever intellectual pursuit he wanted and have obtained results in it. Whether that be software development, mathematics, running a business etc. My point is there are others out there like him, we likely won’t know about them because they aren’t from such affluent families.
That had to do with CP/M not being the standard/mainline OS for the IBM PC (and even then, CP/M was supported but released 6 months after DOS and for 6 times the price), it didn't have to do with IBM selecting Microsoft as their OS developer / vendor, especially since microsoft didn't even have an OS when they were selected.
If Bill Gates weren't from such a well-connected family, it is also likely Microsoft wouldn't have been selected to develop the OS for the IBM PC.