Rakim doesn't seem like a completely money orientated dude at all so I don't think he would have liked to even have the possibility of Kane winning, plus on stage Kane is incredible and Ra is dope but Kane is more of a showman, maybe Ra rationalized it that it would be more about showmanship than lyrics and he didn't want that. Kane would taken a loss better, Rakim has... I wouldn't say ego necessarily, but he takes pride in that sense of supreme untouchability, Kane got pride too but he was confident he could do it and wanted to test his skills.. He seemed down to battle anyone, he wanted to battle Kool Moe Dee back the day, he approached him before he was known and Moe said don't do it to yourself and laughed it off. On stage Kane would have the advantage against Ra I feel, on wax I have no idea, I haven't really heard Rakim do the battle like rhymes in that specific way but Kane does that all the time, Ra is also a true and incredible lyricist though, so he would have some cerebral shyt mixed with an incredible flow. It probably on wax would have been the greatest battle of all time.