(As I recall there are actually some AH stories out based on this idea). But let's consider the issues.
Mohammed is an extremely able individual, the fact that he was practically illiterate makes his accomplishments stand out even more. But one aspect of his life we rarely think about is he also married a very astute woman, who (at least in part) helped to guide his career.
Also, since at least some of his initial success was commercial, which (I think) gave him a base upon which to begin his work)
But I also believe that many of the ideas he based (or God, depend on your POV) Islam on were responses to his cultural environment.
If he converts, and the first part of his life is similar, then his religious response to his environment would be similar. Perhaps a schismatic Arab Christian Church with its patriarch in Mecca?