What are you talking about? Bekele has ran faster than Kipchoge a whooping 1 second. And it's still debatable which course is faster.
Against a guy who won like 7 out of 8 marathons, regardless of the sub 2 attempt Kipchoge is the more likely to come on top. Even considering how unpredictable a marathon can be.
That said, with 3 guys on the verge of running sub 2:03 it has all the ingredients to be the race of the year.