Assuming that Minix adopted a reasonable license and fixed outstanding issues that make Linux currently better, I'm asking you to tell me what's wrong with that. We have a de facto monoculture of Windows on the PC right now and I don't think that's better.
I didn't say what sort of Minix monoculture we might have wound up with. In particular, who says the licensing would have been fixed? Without Linux's success how many people would have thought there was a problem?