Thing is with Bob Marley, without him, would reggae have really been all that different? I mean there were 'nuff roots people out there already, his early ska career (Simmer Down) was influential but again not exactly trail blazing.
Of course he did a lot of highly important tunes, but he was one of many rather than one alone, wasn't he? Marley is the king of reggae, Dennis Brown is the prince, but there were many many others.